I have a numeric column which I can put on a chart with its sum, average etc. I had previously used it in a measure, which still exists and is working. Now when I try to create a new measure, it is not showing up in the list of columns to choose from when I try to use a column based function such as AVERAGE. All the other columns show up but not that one, and it previously showed up when the earlier measure was built. I've tried refreshing, editing the query to remove the column and then restoring it and everything I can think of, but it does not appear in the list when trying to build a measure. It is in my field list and perfectly usable otherwise. It feels like something has become corrupted in my PBIX.
The column names are quite long which is possibly related in some way, but are otherwise working.