Filterboxes disappearing (Sage CRM 2018 R2)

I have created a couple of filter boxes that are linked to lists. In the screen definition of the list , I am entering the name of the filter box in the "Filter Box Name" field. Once the record is saved I have noticed that I what I put in the "Filter Box Name" appears in the CustomContent of the list itself. I then go and delete the text from the CustomContent otherwise it appears at the top of the list when I view it. When I view the list I can see the filter and it works, then bizarrely 5- 10 mins later, the filterbox disappears. When I go back to the screen definition the "Filter Box Name" is empty again!

Has anyone else experienced this behavior ? I can work around the issue by writing custom asp pages rather than using runblocks, but I was trying to avoid that as its quite time consuming!