Filling in attribute data in QGIS; entered data is erased when saved

I have encountered a very frustrating issue for as long as I have used QGIS, across all versions I have used (up to 3.14). I believe it happens with shapefiles only but I have not verified the issue with all other vector formats. Here’s what happens: I open a shapefile’s attribute table, enter edit mode, begin entering text into the various text formatted attribute columns (i.e., going from NULL to a value of some sort), and either exit edit mode or click the save icon. More often than not, some or all of the text edits I just made simply disappear as if I never filled those cells in at all. After I save once, this issue does not persist, so my workaround is to save immediately after entering edit mode, whether or not I’ve made any edits, which seems to prompt QGIS to record edits properly. Being human I often forget to employ my workaround, and become quite frustrated when my hard work is (counterintuitively) erased when I click the save button. Has anyone else experienced this and is there an easy fix?