My server is crashing on player connect starting a few days ago. I filed a ticket with the Modpack (ATM1 v3.03 1.10.2) but on further research it appears this may be an issue with forge.
Server crash log: https://pastebin.com/aR6NnR1k
FML lastest log: https://gist.github.com/checkraze/ce5fa93dd3b93c225e23b90aac490cea
A very similar crash was fixed in forge 1.12.x here: https://github.com/MinecraftForge/MinecraftForge/pull/4312. Nearly identical stack trace to what I'm seeing in 1.10.2. It also appears, based on the changelog and code diffs, that this fix was not back-ported to forge 1.10.x branch.
Thanks for your time!