1)Is Year columns is filtered as "IS prompted" in all reports.
2)If you done any changes in Prompt column formula then Makee the same in Report formula as well and remove the old Filter and keep new year col as "Is prompted"
3)Check the Scope(se as Dashboard) for that Prompt at Edit Dashboard options one more time(hope u done this).
Can you try this by using presentation variables.
Assign the value selected in the prompt to a presentation variable and use the variable in the filter instead of 'IS PROMPTED'.
If required, protect the filter.