Snapshots Pro: PcLZIP invalid filesize error [code -10]

Recently, Snapshots started failing. This error is shown:

ERROR: PcLZIP file:media add failed -10: gzip temporary file '.../snapshots/pclzip-....gz'
has invalid filesize - should be minimum 18 bytes [code -10]

Server is running HHVM (5.6.99-hhvm) <del>but when I stop the service and make the backup process run on the fall-back "normal" PHP (5.6.30), then the error does not occur and files are added to the zip without issue.</del>

I remember there used to be an option to choose the compression method but that seems to have been removed. <del>Any chance Snapshots will become HHVM compatible again?</del>