Okay, got it now.
Checked one of the logs and i reallt think the BC driver is the guilty one here, or maybe not enough virtual memory is allocated.
Sometimes precompilation time is just right (few seconds) :
[2019-06-09 22:47:53] Precompiling program [BUS_ID: 7]
[2019-06-09 22:47:57] Finished program precompilation [BUS_ID: 7]
[2019-06-09 22:47:58] Precompiling program [BUS_ID: 3]
[2019-06-09 22:48:03] Finished program precompilation [BUS_ID: 3]
And sometimes is crazy high (few minutes) :
[2019-06-11 23:47:56] Precompiling program [BUS_ID: 3]
[2019-06-11 23:54:19] Finished program precompilation [BUS_ID: 3]