The devs don’t visit here, this is a user forum. For the devs to look at this you’d need to contact them or open a ticket in your account.
I can’t fix the problem but I can tell you what I think is happening.
Let’s say that you change a text field into a repeater.
The value of the text field would of course be a text value like “this is text”. A repeater field (in the db) will contain the number of rows in the repeater. The issue would only happen if the field type was changed but a post using the field was not updated and would likely happen with get_field() or a have_rows() loop.
Basically, acf gets the repeater row count, I don’t know if there is any checking to make sure the value is an integer. But what could be happening is something like
for (i=0; $i<"this is text"; i++)
Some very strange things can happen depending on what characters are in the string when it is converted to a number for the comparison, and other field types would have very different results.
