New update Upfront Builder Saving problem

Dear Upfront team,

We have had this issue for a while now, but since the update its behaviour changed a bit.

When developing in the builder, CSS changes are not always applied. We have quite a bunch of css code of around 200 lines. Since the update we can see the changes being applied in the builder, but not always on the frontend (sometimes yes, sometimes not). When you reload the builder, the performed css changes disappear...

Here is example of the css file we tried to use:

/* Drie Menu blokken onder logo's */
.upfront #wrapper-1480859665207-1792:hover, .upfront  #wrapper-1480859708167-1576:hover, .upfront #wrapper-1479857401281-1478:hover {
    background-color:white;
}
/* rode blokjes met pijltjes */
.upfront-region-container-region-2, .upfront-region-region-1, .upfront-region-region-3, #wrapper-1484919787141-1052 {
    position: relative;
}
#wrapper-1484915832970-1276 {
    position: relative;
}
#wrapper-1484915832970-1276:after, #wrapper-1484915832970-1276:before {
    top: 100%;
    left: 50%;
    border: solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
	pointer-events: none;
}
#wrapper-1484915832970-1276:after {
	border-top-color: #ufc1;
	border-width: 30px;
	margin-left: -30px;
    }
#wrapper-1484915832970-1276:before {
	border-top-color: #ufc1;
	border-width: 36px;
	margin-left: -36px;
}
.upfront-region-container-region-2:after, .upfront-region-container-region-2:before, .upfront-region-region-1:before, .upfront-region-region-1:after, .upfront-region-region-3:before, .upfront-region-region-3:after, #wrapper-1484919787141-1052:before, #wrapper-1484919787141-1052:after {
    top: 100%;
	left: 50%;
	border: solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
	pointer-events: none;
}

.upfront-region-container-region-2:after, .upfront-region-region-1:after, .upfront-region-region-3:after, #wrapper-1484919787141-1052:after {
	border-color: rgba(213, 116, 51, 0);
	border-top-color: #ufc1;
	border-width: 30px;
	margin-left: -30px;
}
.upfront-region-container-region-2:before, .upfront-region-region-1:before, .upfront-region-region-3:before, #wrapper-1484919787141-1052:before {
	border-color: rgba(194, 225, 245, 0);
	border-top-color: #ufc1;
	border-width: 36px;
	margin-left: -36px;
}
.upfront-region-region-1 .uf_font_icon *, .upfront-region-content-2 .uf_font_icon *, .upfront-region-content-41 .uf_font_icon *, .upfront-region-content .uf_font_icon * {
    position: absolute;
    right: 25px;
    top: 20px;
}

#object-1483916081176-1868:after, #object-1483916081176-1868:before {
    left: 100%;
    top: 50%;
    border: solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
}

#object-1483916081176-1868:after {
	border-color: rgba(246, 246, 246, 0);
	border-left-color: #ufc5;
	border-width: 15px;
	margin-top: -15px;
}
#object-1483916081176-1868:before {
	border-color: rgba(246, 246, 246, 0);
	border-left-color: #ufc5;
	border-width: 21px;
	margin-top: -21px;
}
#object-1483915773306-1182, #object-1483916081176-1868 {
    position: relative;
	background: #ufc5;
	border: 4px solid #ufc5;
    border-radius: 8px;
    margin-top: 10px;
    margin-bottom: 10px;
}
#object-1483915773306-1182:after, #object-1483915773306-1182:before {
	right: 100%;
	top: 50%;
	border: solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
}

#object-1483915773306-1182:after {
	border-color: rgba(246, 246, 246, 0);
	border-right-color: #ufc5;
	border-width: 10px;
	margin-top: -10px;
}
#object-1483915773306-1182:before {
	border-color: rgba(246, 246, 246, 0);
	border-right-color: #ufc5;
	border-width: 21px;
	margin-top: -21px;
}
#text-object-1483912288190-1917 {
    border-right: 2px dotted black;
}
.uposts-part.thumbnail img {
    object-fit: cover;
    height: 350px !important;
    width: 100% !important;
}
/* Plaatjes effecten */
.upfront-region-main  .upfront-image-container img, img {
     transition: all 0.3s ease;
}
.upfront-output-posts:hover img {
    -webkit-transform:scale(1.10); /* Safari and Chrome */
    -moz-transform:scale(1.10); /* Firefox */
    -ms-transform:scale(1.10); /* IE 9 */
    -o-transform:scale(1.10); /* Opera */
     transform:scale(1.10);
}
.upfront-region-main .upfront-image-container:hover img, .upfront #wrapper-1480859665207-1792:hover img, .upfront  #wrapper-1480859546839-1307:hover img, .upfront #wrapper-1480859714479-1584:hover img {
    -webkit-transform:scale(1.10); /* Safari and Chrome */
    -moz-transform:scale(1.10); /* Firefox */
    -ms-transform:scale(1.10); /* IE 9 */
    -o-transform:scale(1.10); /* Opera */
     transform:scale(1.10);
}
#page .upfront-button .button-preset-slidercta.upfront_cta:hover {
    text-decoration:underline;
}
/* Header */
#upfront-region-container-header {
   background-color: #ufc2;
}
#text-object-1481477299731-1003 {
    background: #ufc1;
    margin-left:15px;
}
#text-object-1480861205851-1629 {
    background: #ufc0;
    margin-left:15px;
}
/* Blog */
#page .upfront-output-object.default h3 a {
    font-weight: 300 !important;
}
#page .upfront-output-object.default:hover h3 a {
    color: #ufc1;
}

[data-style="horizontal"] ul.menu > li.menu-item a, div[data-style="vertical"] ul.menu > li.menu-item a {
text-decoration: none;
  position: relative;
}
[data-style="horizontal"] ul.menu > li.menu-item a:after, div[data-style="vertical"] ul.menu > li.menu-item a:after {
border-bottom: 3px solid #ufc1;
content: "";
  transition: 0.4s;
position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
}
[data-style="horizontal"] ul.menu > li.menu-item a:hover:after, div[data-style="vertical"] ul.menu > li.menu-item a:hover:after {
    width:100%;
}
div.upfront-navigation li.menu-item a {
    padding: 6px 0px !important;
    right: 3px;
    margin-left:20px;
    margin-right:20px;
}
.uf_font_icon a:hover {
    color: #ufc1 !important;
}
.uf_font_icon a {
    color: #ufc0 !important;
    transition: all 0.3s ease;
}