Your chance to hit will change based on opponent, your level, and their level.

Meaning in a terrorized zone, your hit chance will be less than that of a non Terrorized zone.

Your chance to hit is a formulae of the ratio between your AR and your opponents defense, along with a multiplier from level difference. Where if your level is higher than your opponents, you get a multiplier greater than 1 (like 1.01) that will increase your hit rate. The inverse is true if you are lower than your opponents level. Where you get a multiplier less than 1 (like .99) that will lower your hit rate.

You will see these numbers on the character sceeen in terms of hit rate fluctuate based on opponent. But there is much more going on behind the scenes than what the character screen indicates.

Long story short, the character screen virtually never provides accurate information. Which is why people that know what they are doing call the character screen the LCS, lying character screen.

For a more thorough explanation with the equation behind it, check here:
https://forums.d2jsp.org/topic.php?t=75247442&f=87

Tyvm been looking around trying to figure this out

Very strange. It's probably a glitch or something. It's very confusing indeed. Lots of people are getting this.

Actually it’s my level versus enemy level

Leveling basically fixed the issue

This is all new information. I dont think anyone else has noticed this yet.

Most are probably too busy getting boosted to 90 to notice

shouldn't be because of leveling, since river of flames has the same area levels as chaos sanc by now? so there should be a noticeable difference at this area already, not just when entering chaos sanc

It was Diablo that I noticed the hit chance droping on the most

Probably uninstall and reinstall helps