so - ok. we'll you made it sound like you fixed your issue - but i guess not.
also you joined in october, so not sure how you have hundreds of hours - cwtn and i do have hundreds/thousands of hours using these, and sometimes we're wrong too.
all of the melee classes uses the same logic for when to assist/move/attack etc - the only classes that assist differently are the pure caster classes (enc, wiz, mage, nec, dru, clr, shm)
I would check your settings like the stuff i mentioned. "inconsistent" almost certainly means there's a setting that you need to adjust.
you said "group tank roles set" - please make sure it is set to group main assist. Might be worth disbanding your group, reforming, and resetting your group roles - sometimes eq bugs out.
did you accidentally turn off usestick?
did you accidentally turn down your assist at value ? i keep mine for all my toons at 100 all the time.
if the location you're in has gaps in your mesh, that would account for that circumstance too - if you get somewhere that we can no longer move, we're not going to be able to move unfortunately
test is getting a rebuild due to other updates the test server build is getting, so might be worth waiting until then anyhow