What is the manufacturing date? This can be easily taken from the S/N - first digits are the year and month.
if it's 20, then is manufactured in 2020 and might need to be updated, there are some issues with the TX manufactured before 2021 using 3080/3090 cards.
Using a Seasonic Titanium 850W with a 3090 KP, had also some random sudden restarts (could only see Kernel 41 in event viewer), these were quite annoying, after reading some similar stuff on forums apparently these power supplies had issues with the transient loads, the OCP/OPP too aggressive also GRW flaw. So even if a hard test like linpack or OCCT is passing, instantaneous change in power draw in games could give surprises though... By the way, I discovered that AC Odyssey or WD Legion Benchmarks beat any synthetic stress app =)) Hours of RealBench, prime95, OCCT, linpack etc passed, but after 3-4 runs of these benchmarks system was crashing :)) The only workaround I saw back then is to undervolt the video card.
Another workaround is to contact Seasonic, or even apply directly for RMA on their website. Their support is excellent to say the least, everything went smooth and pretty fast. Shipment fee to their center is on customer, they will send back a brand new one with FedEx or UPS. Once they received the old power supply, they shipped the replacement the very same day, within hours. Apparently they are aware of the problem, since the 3080/3090 issues Seasonic performed adjustments here and there, so the 2021 power supplies should have this problem solved (this applies also to their Platinum or gold models). The new power supply received is manufactured March 2021 (S/N starts with 2103) and so far never had restarts since.
As a side note, this might be confusing, SSR-850TR is a safety reference used for both PRIME Ultra and PRIME TX in 850W (although they are different animals), as long as any change doesn't require new safety certification, two product with different name can use it.