This is what I get in the log:
2019-03-05 12:59:47 JS CompareField vc: ProdVc field: Math differs, "" <> ""
2019-03-05 12:59:47 JS CompareMatrix (vc name on next line) sizes differs arsz: 3360, h1: 4992, h2: 4992
2019-03-05 13:00:27 JS CompareMatrix (vc name on next line) sizes differs arsz: 3360, h1: 4992, h2: 4992
2019-03-05 13:00:27 JS CompareField vc: ProdVc field: Math differs, "" <> ""
2019-03-05 13:00:27 JS CompareMatrix (vc name on next line) sizes differs arsz: 3360, h1: 4992, h2: 4992

What does it mean?
For example: ProdVc field: Math differs, "" <> ""
How can "" be different from ""?

/Christoffer