There are various issues with mirroring in phat.
Some issues are:
Open Owen_Physics from content examples.
Result: Notice that the mirrored transform is not correct and how its constraint also changes despite not being selected.
Expected: Mirroring should be idempotent.
Result: Constraint becomes entirely free
Expected: Mirroring multiple bodies/constraints should be the same as mirroring each individually
Result: All mirrored bodies become the same a single body. (same shape/dimensions)
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-73343 in the post.