TLDR - multiple Paladins in the theory crafting discord have reported that ever since patch 1.13.3 went live a few weeks ago, Lifestealing enchant and Drain Life procs are not able to crit any longer:
fusionpitToday at 11:58 AM
no crits in 601 casts
https://cdn.discordapp.com/attachments/623550710503571466/660209830169935879/unknown.png
(7.04% spell crit according to dejaclassicstats)
ThelorasToday at 1:08 PM
which weapon is that?
@fusionpit
fusionpitToday at 1:13 PM
Skullflame Shield