My account on the Terraria server is named ()w().
Tank Sentries, when moved, lose all the armour and accessories, only keeping their maximum HP. This was discovered and realised by BobH only a game ago on Beach House, when he moved our Tier 13 Tank Sentry, attempting to stop it from being damaged by an unknown force (Possibly another bug? However, we have not enough information to possibly make a statement on it.). When he placed it back down, it no longer had its visible Berserker Glove and no longer regenerated its Solar Shield, both of which it could of course previously do. It also took full damage from all enemy attacks, implying it truly did lose its armour and accessories and therefore its defense as well. As previously stated, the Tank Sentry did retain its maximum life, however absolutely nothing else appeared to follow it through the move.
We have had a previous encounter with this bug on Bewitched, where a player known as TD moved a Tank in order to keep it out of enemies’ reach, resulting in the loss of its Berserker’s Glove and subsequent demolishing of our Minigun farming setup. We have not tested this bug with any other sentry type, however I do remember from the same game of Bewitched TD moving a Minigun Sentry without it losing its Minishark, and other recent games on Skelotens and Beach House wherein a Snipe Sentry was moved without losing its Sniper Rifle. BobH was the one to move it on Skelotens. This may show that Snipe Sentries are immune to this bug or it may mean the bug does not always occur.
So far, the above incidents are also the only times I saw a Tank Sentry moved. Thus, the probability of the bug’s occurrence is impossible to estimate.
BobH plays on PC, while I play on Mobile, if that is at all relevant.
With some fresh testing, Bob has recorded the glitch in action:
As you can see, it loses its glove. It then proceeded to take full damage and not control aggro, just like all the others before it.
We then shortly after tested with a Minigun Sentry and found it immune to the glitch, keeping everything post-move.