Primay (internal) Battery 601 error

[stefaniafg]

Good morning, I have a ProBook 450 G8 that's been giving me battery problems for some time. It started with this error last year, so after testing with HP's support suite, I replaced the battery with one with the same code, as indicated by the test program.

It worked fine for a couple of months, and now it's giving me the same error again, but randomly, even when the notebook is plugged in with the adapter (but if it's plugged in, what difference does it make whether the battery works or not? Shouldn't it stay on anyway?). Without any warning, even with a fully charged battery (whether plugged in with the original adapter or not, never replaced), it shuts down without any warning, going from 99% battery to 0. When restarted, it gives the above error, and obviously the battery test fails, saying it's not present. However, after a few restarts (without being plugged in), it suddenly sees that it's charged again and boots up without any problems. It does this completely randomly, sometimes after 2 hours of use, sometimes after 5 minutes.
I tried the tests indicated, starting before Windows, but no problems were found.

So I don't understand what the problem is. I don't think it's the battery itself, because the same thing happened with the one I had previously (which was the one I received when I purchased the laptop).
Can anyone tell me where the problem might be? Thanks so much!