Brewin and Chewin incompatibility after FD 1.3 update - keg ticking crash

[BaronHog]

Minecraft version

1.21.1

Farmer's Delight version

1.3.1

NeoForge version

21.1.225

Description

Forwarded from Farmer's Delight issues
vectorwing/FarmersDelight#1309

[DelsinPRO]

Crash Log (tested in an isolated instance)
https://mclo.gs/CB0FhRs

[SlytherTheUndertaker]

I got the same crash in my 1.20.1 world

[deadly-pudding]

I don't have a huge amount to contribute here, but the null pointer exception is thrown at https://github.com/ChrysanthCow/BrewinAndChewin/blob/df3c5e02fe654356781b3f7ee0ada35d7fdc26f3/common/src/main/java/umpaz/brewinandchewin/common/block/entity/KegBlockEntity.java#L501

which makes me think that one of the filters in that int declaration/assignment is returning null and screwing up the sum() at the end. My best guess is Farmer's changed how Heat and Freeze sources work?