After another test of sorts, it's not the lump causing the issue. I ran a load of lump and let it burn down completely and the lower grate vents were almost covered completely, but the lump did burn all the way down during the process. I will be replacing the grate. I plan to use the smokey joe charcoal grate until I can find out if the high-que grate will fit or not.
Kamado Joe Big Joe ° Kamado Joe Classic ° Old Country BBQ Pits Brazos Offset
UDS ° Traeger Lil' Texas Elite