EBS 12.1.3 frmweb.exe began to use a lot of cpu until server crash

Hi,

It began 3 days ago.  We have 2 servers with forms/web(libqc50 and libqc51), 1 server with CM(libqc52), 1 db server(libqc49).

We've never had that king of problem before. Before the middle of the day.

Everyday is the same:

At around 9AM, always on the same problematic server, the first frmweb.exe begin to use 25% of the CPU.

A bit later, a second one start to consume 25% also.

At around 12:00, there are 4 of them, consuming exactly 25% each, that add up to 100% .

Someone can help on that ?  Is there an efficient way to diagnose the problem ?

Patrick