Hello Yoann,
As for the processing time, we would need the log at least from 1.7.3 version related to the depth maps generation.
Regarding the dense cloud on the screenshot that has a lot of holes, it seems that the project is different from the one that you have shared. can you share the problematic project as well?
Also please check, if you observe any difference in respect of presence of such large holes, if Mild filtering option is used.
If you are using any tweaks related to the depth maps or dense cloud, please also name them and assigned values.