If the previous failure was disastrous (output mosfets exploded) you have to check all gate resistors, even a small variation from the value in tolerance, it can mean a big difference during the operation of the amplifier (so it can cause big problems, too not immediately) also you have to check especially the "VS" resistors (which are the 4 resistors of 1 or 2.2 or 4.7ohm that reach the "VS" pins of each IRS21844, when the failure of the amplifier is catastrophic, these are the first resistors that open or modify their value / behavior, even in this case, reading values after all "in the norm", does not necessarily mean that these resistors have perfectly survived the catastrophe (my advice is to replace them regardless, because they represent a point VERY IMPORTANT for your high side).
On the driverboard, there are some resistors that you can break or change their value when a catastrophic failure also leads to the failure of some smd transistors (even when nothing else fails) I for safety, I always replace everything, it costs you little money and little time and you avoid wasting more money and time later.
For the rest, if your amp really has everything else in place, then I could think of some "vias" that no longer work, otherwise nothing else.
Oh, I forgot, did you check the "VB" diodes on the driverboard?
What Output fets have you used ?
If i remember, HV version of this board, use 500v mosfet, so if you have used 400V (like irfp360lc or fda24n40f) you had not problem on the bench probably because on the bench you use 12 or closest volt power supply, so the amp PS don't reach a very high (and problematic) rail voltage, but in a car, with 14v (also with 13.7v) the amp ps section have produced a biiiig rail voltage that destroied your output fets and for the first time the protection circuit have saved you.
When you had turn on again the amp, the protection was not fast enough to protect you and the shorted output section have caused the catastrophic blown in ps section.