They submitted the alternate slate of electors in case Congress refused to accept certain states electors because of the possibility of fraud in a state.
If they had thrown out a state’s electors that risked that state not having a say in the electoral college electing the president. The alternate slate of electors would have protected a state from that.
They openly submitted them to Congress; it was no secret scheme. Would a car thief go to the motor vehicle dept and try and submit an alternate registration KNOWING there is already a registration on file, and openly admitting it to the clerk?
That was the only reason they did it. There is/was no criminal intent.