We have swapped the mirror mount of LB_M6 and LB_M7 from newport ones (picture 1) to Polaris_Thorlabs ones (picture 2). The newport are suspected to be unstable since they show some "hysteresys" when moving the micrometer adjusters forward and backward.

We 've checked it did not impact on the overall power.

This should help in long term stability although it is unlikely that this will cure the neoVAN beam drift mentionned in 41742