ok :
I've open the alembic file you send, so...
first : this can be cool to rename correctly and group your mesh, it will definitly help you...
then :
it might some muscle like this one have self intersection
And, I've lauch a self intersection test frame by frame and the result is :
FRAME : 1
lMuscle_12.f[42]
lMuscle_12.f[44]
lMuscle_13.f[3164]
lMuscle_13.f[3215]
lMuscle_15.f[22]
lMuscle_15.f[52]
lMuscle_15.f[4070]
lMuscle_21.f[25]
lMuscle_21.f[1131]
lMuscle_31.f[201:202]
lMuscle_31.f[231]
lMuscle_31.f[240]
lMuscle_31.f[613:614]
lMuscle_31.f[616]
rMuscle_4.f[25]
rMuscle_4.f[1131]
rMuscle_27.f[22]
rMuscle_27.f[52]
rMuscle_27.f[4070]
rMuscle_29.f[3164]
rMuscle_29.f[3215]
rMuscle_30.f[42]
rMuscle_30.f[44]
rMuscle_34.f[201:202]
rMuscle_34.f[231]
rMuscle_34.f[240]
rMuscle_34.f[613:614]
rMuscle_34.f[616]
FRAME : 2
lMuscle_12.f[42]
lMuscle_12.f[44]
lMuscle_13.f[3164]
lMuscle_13.f[3215]
lMuscle_15.f[22]
lMuscle_15.f[52]
lMuscle_15.f[4070]
lMuscle_21.f[25]
lMuscle_21.f[1131]
lMuscle_31.f[201:202]
lMuscle_31.f[231]
lMuscle_31.f[240]
lMuscle_31.f[613:614]
lMuscle_31.f[616]
rMuscle_4.f[25]
rMuscle_4.f[1131]
rMuscle_27.f[22]
rMuscle_27.f[52]
rMuscle_27.f[4070]
rMuscle_29.f[3164]
rMuscle_29.f[3215]
rMuscle_30.f[42]
rMuscle_30.f[44]
rMuscle_34.f[201:202]
rMuscle_34.f[231]
rMuscle_34.f[240]
rMuscle_34.f[613:614]
rMuscle_34.f[616]
FRAME : 3
lMuscle_12.f[42]
lMuscle_12.f[44]
lMuscle_13.f[3164]
lMuscle_13.f[3215]
lMuscle_15.f[22]
lMuscle_15.f[52]
lMuscle_15.f[4070]
lMuscle_21.f[25]
lMuscle_21.f[1131]
lMuscle_31.f[201:202]
lMuscle_31.f[231]
lMuscle_31.f[240]
lMuscle_31.f[613:614]
lMuscle_31.f[616]
rMuscle_4.f[25]
rMuscle_4.f[1131]
rMuscle_27.f[22]
rMuscle_27.f[52]
rMuscle_27.f[4070]
rMuscle_29.f[3164]
rMuscle_29.f[3215]
rMuscle_30.f[42]
rMuscle_30.f[44]
rMuscle_34.f[201:202]
rMuscle_34.f[231]
rMuscle_34.f[240]
rMuscle_34.f[613:614]
rMuscle_34.f[616]
soooo, good luck 😃