Text blinks and disappears from textbox, table, button, etc. in story view, disabling me from meaningfully working

Text incessantly blinks in text box, table, button, etc. as I type. Upon clicking outside of text box, etc.,, the entire text box, table, button disappears. the text is not visible on the story view slide at all, making it impossible to manipulate. It's present in Timeline, and the "eye" icon indicates "show." It also appears when slide is previewed. Does anybody know why the text incessantly blinks and then disappears after it's inserted into anything? Thanks.