I've never had brushes do it but the mops with a patch on it i jam hard into the action and turn allot and this bunch keeps coming apart so i soldered them.Interesting I never thought to do that but I also never had one come apart in the barrel.
Are you sure they are Pro Shot ??I bought a bunch of pro shot brushes in individual packaging recently and funny thing after a pass down the barrel on the pass back the brush pulls out of the threaded holder, I’ve been using pro shot for ever and this has never happened I took a look at the swagging and it is decidedly different then some older pro shot brushes ( see photos)