Penance brand AoE interacts badly with Brand Mastery (#1516796639)

Bug reference #1516796639
Related to https://www.pathofexile.com/forum/post-reply/3456112

The AoE on a penance rune seems to depend on how long it has been attached.
If you take the Brand Mastery which causes brands to move every time they activate (max every 0.3s), then the effect is FAR more obvious, also adds compound bug, which I will explain further below.
I have no reliable info on whether damage is affected also, as the brand damage is so high it's hard to reliably test.

Steps to reproduce the bug reliably:
Take penance brand, and the brand mastery which makes brands change target on activation.
Take Runebinder so that you can attach more than one brand to a target

Small AoE:
- Isolate a single target
- Cast 2 penance brands on the same target
- AoE will be significantly smaller than a single brand, as noted in the other linked bug above.

Bigger AoE
- Take at most 4 enemies together (related bug detailed below)
- Cast penance brand on any one of them.
- Wait for the detonation
- AoE of the result will be much bigger than usual, with bigger AoE depending on how long it has been active. (results will vary depending on random jumping and how long it takes to build one target up to 20 energy)

Notes:
In both cases, all energy generated on every enemy touched by the triggering brand will be removed, not just the final target.
If the brand is detached by the target dying, the energy effect will remain on corpses until the brand expires.

The images here are all in the same area with no changes in gearing, level, shrines etc.
The only change is how long I let the brands act (by larger or smaller groups)
I've seen smaller detonations, but couldn't capture one in this area






Associated Bug:
If a penance brand lasts long enough, it will stop generating charges.
This is much harder to reproduce, but if you cast a single brand into a large horde, it will eventually stop charging up enemies.
At this point, it will remain attached indefinitely (or continue to jump if there are targets close enough), still counting towards your maximum number of attached brands.
I have had an enemy with 2 brands attached, as the last remaining enemy, with both brands "out of charge", so I couldn't attach any more.
I had to lure it into other enemies to be able to finish it off, by detoating them.