From the pinned Player List of Known Issues thread at the top of the forum…
From the pinned How to Write a Good Bug Report thread at the top of the forum…
Please use the Search feature to search the forum and see what bugs are posted.
The previous 33 Bug Report threads that mention gelatinous
The previous 38 Bug Report threads that mention blue goblin
Yes, it’s definitely a bug.
Increased reporting of this issue coincides nicely with the rework to the Monk’s Mystic Allies build, because the allies cause huge damage and cannot be paused between the goblin splitting.