Hi there, I'm glad to see you're still active here and responding to other threads :)
I think I ran into a nasty bug with the Neutronium Payloads item; somehow, after having taken it along with some other passives, my explosive damage got reduced several times, to the point it was as low as ~20% at a point where it should've been over 100% instead. Here's a timeline of my damage value and the items I took (or items that interact with explosions/explosive damage), to the best of my abilities/memory:
- One of my first items in the run was Blood Sacrifice, which procced the full 3 times, leaving me at an assumed 112% explosive damage. 'Assumed' because I didn't look at my stats, given I already am quite familiar with the game & the particular item.
- Up until getting Neutronium Payloads, I'm pretty sure none of the other items I got modified explosions or their damage in any notable way - sadly I didn't think of taking a screenshot in the pause menu before my run ended unexpectedly, as I was still trying to collect more items that modified explosions to see how things evolved, so I don't know exactly which items I had or in which order, thus I'll only be naming the ones I can confidently remember.
- After getting NP, I don't immediately check my stats, but I soon notice my explosive weapons (mostly the HE Rail) underperforming, so after one or maybe two more intermissions - during this time is when I'm pretty sure I took my first stack of Predictive Shrapnel - I check my stats and it turns out my explosive damage is around 43%! At this point, unless the wording is wrong, it should be ~112 - 25 = 87%. Somehow, it's as if my damage had halved out of nowhere.
- Unsure of why this happened, I keep playing and keep focusing on collecting explosives related items; my memory is fuzzy regarding which I took first or when relative to when I check my damage again, but somehow I end up with my exp. damage at ~20% despite having at least Radical Decals (+5) and HE Ammo (+10), and potentially other items that boost it. And at some point I also got a second stack of Predictive Shrapnel.
- I continue playing, get another HE Ammo stack, some other damage items, etc., and before I died I think my damage was building back up to around 50-60%. Super low compared to what it should've been, and while it isn't a great point of reference (cause it gets favored a lot) my kinetic damage was ~180% I think. In practical terms, it ruined the explosives build completely and to the average player would've potentially ruined the whole run itself.
My gut instinct makes me think that maybe something goes wrong with the interaction of NP and PS? Because I had two stacks of it, and they seemed to somewhat line up with the two instances of my damage lowering by a lot (I felt like it was potentially getting halved, given the numbers).
This whole thing makes me wish there was some sort of dev console or modability to the game that allowed me to spawn those items in myself to test this, or create a ship loadout that has them from the start vs one with just the one of them, to quickly test for myself why this is happening. As I understand it though, such a thing might not even be possible on a technical level for this game, aye?
Anyways, I hope you can track this down and fix it at some point; NP was already an item I was super hesitant about, because it didn't seem much good except against big/slow enemies, so I barely played with it until now where I came across it during an explosives build run and wanted to experiment. Now, I don't think I'll even take it again. Hell, maybe the bug isn't actually caused/related to NP, but I've built around explosives a lot and never noticed any bugs as major as this one, so it's my only guess as to why this might have happened as every other item I picked, I was very familiar with and hadn't had issues with.
Hope this helps