Construction Heuristic Phase slower since migration from 7.28 to 8.14

Question

After migrating Optaplanner from version 7.28.0.FINAL to version 8.14.1.FINAL, the construction heuristic phase defined in the configuration as following :

  <constructionHeuristic>
    <constructionHeuristicType>STRONGEST_FIT</constructionHeuristicType>
  </constructionHeuristic>

is significantly slower than previous. When using V7.28 the solver is able to process with a score calculation speed of 6446/sec vs 102/sec (50 times slower) with the version 8.14

There were no changes in the constraints.drl, no change in the model except that the PlanningEntity movableEntitySelectionFilter field has been removed and replaced by a pinningFilter (that has the opposite logic implemented). Aside from that and the different migration upgrade, I cannot explain nor fix the drop of performance for the first phase. It is not critical, as it takes "only" 30 to 50 minutes to finish the CH phase (instead of 2-5 minutes before).

Is it possible that some performance shift have happened (that would require a different configuration) since the v7 for the CH phase? I've read the doc about scaling CH, but I don't think any is linked to this drop of performance.

EDIT, after profiling the task that execute the solver.solve(), here is a snapshot of the CPU time :