This incident has been resolved. Microsoft has published a fix on LUIS about this issue.
Posted Sep 27, 2019 - 10:25 CEST
Investigating
We are aware that some of date resolution provided by Microsoft LUIS are incorect. We are working with Microsoft support to make sure everything goes back to normal quickly. Sentences containing "la semaine prochaine" will not be resolved properly
All others functionnality and sentances are corrects.