Split Coil wiring gremlin

Has anyone had a coil stop working on a Tonerider humbucker?

Wired up my EX-1 with 2 Bourns mini 500k A push/pulls and it was working like a charm. Sadly it had been left in its case for over a year and when dragged out one day around xmas I found that bridge PUP was only operating on one coil and the push/pull no longer working?

Initially I thought it may be a faulty switch but when running a multi meter over the wires I get 4.22k reading across red & black which is for the north slug coil but nothing but "1" across green & white for the south screw coil? Bridge PUP is rated at 8.3k so 4.22k for one coil is about right.

Checked this out on a spare 4 wire humbucker and there should be same reading on opposing coils.

Looking forward to some expert replies before I rip out the PUP and send back under their 5 year warranty for a replacement.