Using newest version of both new blog templates and membership. New blog template v1.8 and Membership v126.96.36.199. Looking at logs though, this has been an issue for over a month for us. We try and keep most plugins up-to-date so this could be related to the most recent version (v1.8) released end of june, or possibly prior. Upon research, it was found that this issue existed about 3 months ago but was resolved. Was this bug possibly re-introduced? This was working fine until recently and we've made no other real changes in plugins other than performing updates.
99% of our plugins are MPMUDev plugins as well and we have not installed any non-wpmudev plugins for well over 6-8 months minimum. So the possibility of another plugin causing this conflict is minimal. Please have the developer look at this to ensure the bug was not reintroduced.