I have a plain vanilla tiddlywiki with a couple of tiddlers.
I copied this on my Android smartphone. And opened it with tiddloid.
All went well till I was only viewing the tiddlers.
But after I edited/ added new tiddlers, some html markup strings started appearing at the very end. They are not part of any tiddler. And they continue to show even after I close all the tiddlers and hide the sidebar.
I copied the wiki back to my desktop and opened it with TiddlyDesktop. The html markup strings continue to appear and behave the same way. I can select them, copy them but can not delete them.
There seems to be no problem with the wiki otherwise — I can open tiddlers, edit tiddlers, etc.
I get the same sort of thing with both Tiddloid and Tiddloid Lite. I suspect it is a problem with Tiddloid as I can get the code to disappear if I open it in either Tiddloid version, save and close it then open it in the other Tiddloid and save and close it, but this is only a very temporary solution I’m afraid; the code comes back pretty quickly.
I am not so sure how to help you but in the past I have seen random tiddlers or their content transcluded when a filter is broken and the result is some artifact. So if you can find the page template, or something tagged $:/tags/BelowStory with a filter in it and fix the filter you may stop it.
I’ve found the same issue today (both Tiddloid and Tiddloid Lite, latest versions), Android 11 (not an issue on Android 8).
The code appears to belong to the boot.js core tiddler and I suspect it’s related to the encryption mechanism (though I’m not sure).
Steps to reproduce:
Open an (encrypted) TiddlyWiki in Tiddloid or Tiddloid Lite (on Android 11)
Save the wiki
Reopen the wiki
The code appears “underneath” tiddler frame after the wiki is saved by Tiddloid/Tiddloid Lite and then reopened. Once it’s saved like this, the code will show on any mobile or desktop browser, it appears “burned in” but how much of the code is revealed depends on the height of the tiddler.