As a papercut type issue, the left-hand menu consistently resets itself to have *just* the dictionary link off screen, aligned perfectly, leaving no affordance to identify that it can scroll. At this point I've internalized scrolling to get to Dictionary, but after encountering this seemingly daily for a month (since my classes resumed) I figured I'd note it.
I have not identified the series of actions that results in this outcome, but my common use-cases have me switching in and out of Pleco from a custom Anki card (plecoapi://x-callback-url/s?q={{Field Name}}), copying and pasting across multiple devices (using clipboard sharing), and switching between the Clipboard Reader and Dictionary (via the search button at the top, where I proceed to review example sentences to try and figure out register since, well, Cantonese). I typically access "Clipboard Reader" via "Recent Documents" so that I don't have to click through the "Reader?" popup.
This is not a big deal and not worth addressing if it is some weird artifact only I encounter by virtue of my usage pattern. Maybe see if you notice it in your own testing? I'll come back and update this with a precise reproduction if I can identify how to do so consistently. (iPhone XS)