You’re not ranting, you’re not rambling, it’s a known bug that has been discussed in detail. There are others, but see Thrall not attacking issue for the latest rather long discussion. Within, @Ignasi says the devs have acknowledged the problem, but someone decided a few tests warranted putting ‘cannot replicate’ on the Trello card. I can’t even find the card anymore (have a link?), but it was labelled ‘Prioritization’ last November or December, which was completely ignored.
I had posted explicit instructions on how to duplicate it including place, procedure and implored them to retest until it happened. Apparently, it was also ignored.
It is a bug.
This is what I use to bypass it.
I have two main followers, Seeker Iris, one in black, the other in white. I only arm them at my main base in guard mode with both a sword (Blade of the Adventurer?) and a truncheon. In semi-regular runs, I go through a level on the east end of Sep. If there are T4s I want, I remove the sword from her inventory. If not, I remove her truncheon. She will assume one of three AI responses.
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- When I attack, she will go berserk, attacking anything in her line of sight. This is what tells me she is on the right AI track for the Unnamed City
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- When I attack, she remains passive and will be ineffective until server reset, perhaps longer.
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- When I attack, she will menace, but not attack, the NPC closest to her current position.
In case 1, she is ready to go.
For case 2, I return her to base and pull out the other one. Same gear, the only difference is the color of her heavy armor. Then I repeat the Sep process. Usually, this one enters case 1 and I am ready to go. If not, I am done for the day because two is all I got 
In case 3, she could revert to case 1 and I continue to slaughter innocent civilians. Sometime getting hit causes the change. There is no clear cue as to cause.
Again, identical thralls geared the same. Random bugs are hard to track down and I understand the problems Funcom faces now with exploits and things that prevent players from even playing. Priorities.
Thralls are a big part of my game, and I can safely assume most who solo (even online, like I do) feel the same. Unfortunately, since there has been no action on the part of the developers, most have given up imploring.
I submit that longevity of a bug that affects a significant portion of the playerbase be included during prioritization.
I hope this helps in two ways, reiteration of the bug, and potential workarounds.
Now, how is that for a rant?
Regards, and thanks for most of the game.
jim