Reported issue on FTB Forum, hopefully the FTB team sees it soon. Here is the link to that post.
To sum up: Updated server to 1.4.0 of DW20 1.18, player joined, server crash, ticking tile entity. Crash report is here. Enabled Forge Erroring Entity removal, server restarted. Player could not interact with barrel, attempted to make a new barrel, client crash to desktop.

Already fixed, please update SGC