I’d guess that way you have arranged them is causing them to cancel out each others fields?

Maybe you need to re-align your poles..?

Very strange, no way should glue mess up a magnet.  If the magnetism has gone, won’t come back on it’s own.  Replace the magnets.

Maybe something happened to them whilst the fibre was being replaced.  Dropped, or got hot somehow?   Heat and mechanical shock are both very bad for magnets.  Neodymium magnets being made of sintered powder are mechanically weak – are they in good physical condition?

Eclipse used to warn against disassembling their older chucks.  The problem was due to Alinco, then best magnetic alloy, except the flux needed to be managed. Not likely to be Bill’s problem – Neodymium should be fine.

I blame Gremlins!

Dave

They also really don’t like having their plating damaged!  Once exposed to air the material can degrade.