Baby Zombies and variants (even baby husks) burn in daylight

Please force a crash by pressing F:+C for 10 seconds and attach it here.

Is this because I'm using mods?

Possibly. Are you able to reproduce this in vanilla Minecraft? Also, using mods invalidates your bug report, as these are unsupported by Mojang.

How nice:

WARNING: coremods are present:
LoadingPlugin (Quark-r1.2-74.jar)
Contact their authors BEFORE contacting forge

Even says to contact the mod makers.

OK, issue resolved. Caused by a mod. Sorry.