Happened last night multiple times on Grobbulus, and once with abolish disease on Heigan.
Believe it has something to do with level of spell cast (Cure disease resists more than abolish)
Remove Lesser Curse also had a single resist on Noth.
I can’t include links so no logs, but i’ve double and triple checked them.
Our guild was experiencing the same issues last night. Normally our priest who does Cure Disease on Grobbulus is on point for each one, but last night she had to do 2-3 casts of Cure Disease on people because they kept getting resisted.
Same thing happening here. Taking a long time to remove buffs in PvP (which is slightly problematic).
Please fix 
Same here. Just did Grobbulus and poisons dispels were getting resisted. As funny as it was to hear the priest panic on discord, this is not a good bug.
Low level anti venoms are being consumed when used but no longer removing certain poisons. Used to always remove, if they don’t work on the poison it should just not be consumed no?
Could be that there was a built in chance to resist dispel we did not know about and its now working correctly? No idea, I have seen this also. I hope they either address this or explain the situation, would be nice to know.
This pretty much nails it on the head. This was a bug fix that didn’t make it into the patch notes.
In 1.12 and all of Original WoW, it was possible for dispels to be resisted. This was correct and intended in 2006, and simply went unnoticed until now in Classic. During 1.13.7 development we found the offending incorrect code and fixed the issue.
This means that offensive dispelling in pvp may not always succeed, particularly if the target you are trying to dispel is significantly higher level than you, as level disparity does affect this. Additionally, dispelling of harmful affects in certain pve encounters will also have a small chance to fail.
Thank you for the observations around this! But this is, in fact, intended and correct.