SSRS - Batch printing grouping Issue? Report seems to be randomly messing up PO Number and page numbering

Question

I'm using MS Report Builder v15.0.19210.0.

I have an SSRS report that is driving me crazy. If it is used to print a PO individually, all is well. The issue starts when the report style is used to print a batch. When used to print a batch, some of the POs are printing with the following fields sometimes incorrect: -PO Numbers (sometimes jump to next PO # on pages after first page of PO) -Order Date (sometimes blank on pages after first page of PO)

The last batch was 45 pages and included 29 Purchase Orders. All look good until page 14, where on page 2 of the PO, the PO number changes. (It's supposed to be 23661 but it shows 23662.) Then after that, PO numbers are incorrect on many pages (after the first page) on each PO.

PO Number on first page of PO PO Number on second page of PO

I have been working on this for a week, but I'm not getting there. It must be something with the grouping, but I can't find it and I'm afraid I'm making it worse. Can anyone point me in the right direction? In the meantime, my Purchasing Dept is having to print these individually, which is not ideal.

I would really appreciate any help. If I haven't given enough relevant info, please let me know what I'm missing. I'm not sure what to post, and I don't see a way to attach the .rdl.

Thank you, Erin