I have noticed a number of named range references in VBA suddenly causing errors in the last few weeks as well. The named range appears normal in the name editor but cannot be referenced in VBA. Even deleting the named range and recreating it with the same name still fails. Deleting it and recreating it with a different name does work though. However deleting a named range is not a great solution if it's also referenced in formulas in the workbook, as that is going to break them all.
In addition we also seem to have found an issue where named range references inside of an Excel formulas itself that was being used as a conditional check is functionally silently failing. Evaluation of the formula shows the error, but it's otherwise not obvious because the formulate still "functions" while always defaults to the fallback state of the conditional check.
Clearly something has gone very wrong with named ranges in a recent Excel update, which seems like a kind of huge deal to break.
Going to look into the ability to rollback to an earlier version here as well...