PS5 powering off after a couple seconds

PS5 came into my shop for a broken HDMI port. The HDMI port was replaced successfully, ps5 was reassembled, tested, and returned to the customer. The customer then called back reporting that it was shutting off on them. I directed him to bring it back in, we tested it, and it didn’t shut off for us while he was standing there. We waited for about 5 minutes for it to shut off and I asked him how long it normally takes. He told me it was almost immediately, like 5 seconds, and this was the longest it had been on. I told him I would test it for a little bit longer, so he ended up leaving it with me. After about a total of 7 minutes, 2 minutes after he left, the PS5 finally shut off.

I assumed this was a thermal event considering it shut off for him after 5 seconds, but had stayed on for longer with me, and decided to order some new Liquid Metal. I removed the old Liquid Metal, fully cleaned the APU and the heatsink and reapplied a drop to the APU and another slightly smaller drop to the heatsink. I was successful in fully spreading the Liquid Metal across the APU and heatsink, and reassembled it again. The ps5 powered up, stayed on for about 15-20 seconds, then shut off again. I turned it on again, this time it stayed on for about 5-10 seconds and shut off.

This is the issue that was happening before reapplying Liquid Metal, which leads me to believe it’s not related to Liquid Metal, but I have no idea what it could be related to and what else I should look into. Any help is appreciated.