I don't if you followed through on this but I've had the same problem several times.
It seems this happens everytime you select a time period that is outside of the model calendar but is inside one of your time ranges. In the classic UI everythings works fine but in the New UX, it displays just "Find...". It does not have any impact on calculations, it is just a display problem.
What is the calendar setting of the module in which the line items sits? If you are using a time range just for the line item while the overall module time frame is set as the calendar time this may be what is causing your problem. In the UX you allocate the module to the field card and I suspect that the module settings are then applied universally to that card.
It happens on field cards when using a time range outside the model calendar range.
I contacted the Anaplan support on this topic back in october last year. I was told it was indeed identified as a bug by the Product Team and that it was planned to be fixed in a future release. It has not been fixed as of today though.
The only solution i can think of is to extend to model calendar range so that it contains the year FY23 and FY24, but you may not want to do this for other reasons. However, even though it displays "Find...", the value stored is still the right one, so it does not impact your calculation, only what you see on the field card.