Kind of.
If we had several states fraudulently send INCORRECT slates of electors, that is where the problem is. Yes, electors voted for Biden, but if they were there due to fraud, then what?
There is no Federal constitutional entitlement to be appointed as an Elector.
Appointment is a reserved power of State Legislatures, and only State Legislatures.
Given that there were 63 days between November 3, 2020 and January 6, 2021, and given that no State Legislature objected, or even raised a question, I would say that the persons who presented themselves as appointed Electors and voted had every right to have their votes counted, and for their choice to be sworn in.