On 1.16.5, sometimes an instance with Citadel installed can enter an apparently permanent broken state in which launching in offline mode will always cause a soft freeze during texture atlas stitching, either at blocks.png or at shulker_boxes.png. During this soft freeze, heap usage will increase at around 1mb/s, but no further loading progress will be made.

I've disabled all the other mods I'm using and confirmed Citadel is definitely the problem. The instance launches fine even with everything but Citadel enabled, and the soft freeze occurs even with nothing but Citadel enabled.

I don't know the circumstances that cause this persistent broken state in an instance. I know it's something other than simply offline mode itself, as my instance with Citadel installed has worked in offline mode before. Additionally, due to changes in my Internet connection situation, I'm unable to assess whether or not launching in online mode resolves the issue. Sorry I can't be of more help.

Log at following link: https://pastebin.com/MtFJKs7x
Wrapper command no-oom doesn't modify the Java environment, it just tells the system OOM killer not to kill it.