3rd copper layer in a 4 layer PCB board not showing up whiole and after Importing from Altium

Layout
1

I was trying to import a 4 layer Altium Board, but the 3rd layer does not show up at all.
So Nor auto layer matching or manual could be done and this was one copper layer is completely missing. What could be the cause and how could I find a workaround?

Thanks

2

We’ll need an example board to diagnose this issue. You can report a bug using the Help->Report Bug menu option. Attach the Altium board there with steps to recreate the issue.

3

Thanks. I will keep looking for potenitial problems, and if nothing helps, I will report the bug. Interestilgly when trying to Import it into Eagle, the same Problem happens…

4

The problem will continue to exist even if you find a work around. If possible, it would help to have a reproducible test case so that we can fix the problem for everyone