In MW, annotations loaded from the document will have data-parsoid attributes, and so will have difference store indexes to new annotations. If two words with differently indexed bold annotations are placed side-by-side they converter will close the first one before opening the second, e.g.:

<b>Bold on load text</b><b>added text</b>

Which Parsoid converts to

'''Bold on load text''''''added text'''

Version: unspecified
Severity: normal