PR's not getting deleted and recreated during MRP run

Hi,

Could someone please explain the following:

We have MRP running every night with processing key NETCH and planning mode 3 (delete and recreate planning data). We noticed that for some materials with MRP type V2 (automatic reorder point planning) and lot size HB (replenish to maximum stock level) the MRP is not working, i.e. no PR's were created even though the stock went below the reorder point. When looking at the stock/requirements list for a certain material there's just the stock, no other MRP elements. In the MRP list, however, it shows a PR created for the correct amount, but when trying to look at that PR, it says PR doesn't exist.

So apparently a PR was created in the next MRP run after the stock went below the reorder point but since the PR was not confirmed during the following day, something went wrong in the next MRP run. Shouldn't the system just have deleted this PR and created a new one, isn't that what planning mode 3 is for? Instead, the "deleted" PR seems to be hanging somewhere and preventing the MRP from creating a new PR?

Any ideas on what is happening, why and how to fix it are very much appreciated. The system in question is Retail, if that makes any difference.

Thanks in advance.

Br,

Henna