PWB Design - Soldermask Application and Vias as Test points

[sunybeet1987]

My company uses Incircuit Tests as much as possible. Manufacturing Engineering has changed printed circuit board suppliers. The New supplier solders is filling the vias so the test probes are not making contact with circuit. The solder mask does not constantly fill the same vias. There is a requirement to cover all vias under any components. I read some comments about how vias should not be used as ICT Test points and the vias should be covered for production.

My question is what causes the soldermask to fill the vias on standard .062" thick pwb? Why would this happen changing suppliers? Any suggestions for notes to be added to the pwb prints to handle this issue?

Thanks,

Greg