This bug was first reported by [[ https://en.wikipedia.org/wiki/User:Jessicapierce | User:Jessicapierce ]] on 27 June 2019.
**Steps to Reproduce:**
Unknown as of yet, but occurs on some occasions when adding or editing citations in an article using VisualEditor.
**Actual Results:**
Numerous strings and alphanumerical characters are substituted into the affected text from neighbouring sentences, including their own citations, resulting in garbled text with some letters substituted by pipes and equals signs. Nowiki tags are placed all across the mess, sometimes corresponding to non-markup text (sentences) that has been implanted but sometimes not.
- [[ https://en.wikipedia.org/w/index.php?title=Naveen_John&type=revision&diff=904496575&oldid=896239961 | Example 1 ]] – a sentence is removed and replaced by a paragraph with a new citation at the end, but this garbles the unrelated citation preceding the removed sentence by substituting various pipes and equals signs inside it, as well as substituting the 2 first words of the removed sentence. All subsequent citations in the entire article are garbled by similar removals of neighbouring sentences and/or citations.
- [[ https://en.wikipedia.org/w/index.php?title=Prion&type=revision&diff=903750176&oldid=903510847 | Example 2 ]] – a new citation is added to a sentence with 3 existing citations, but this garbles all previous citations (not the new one) by substituting a garbled version of the sentence after the new citation (with equals signs and pipes substituted inside it at random) and substituting various parts of the existing citations into the ones previous.
- [[ https://en.wikipedia.org/w/index.php?title=Patricia_Jacobs&type=revision&diff=903747492&oldid=895577726 | Example 3 ]] – a citation is replaced with one used previously in the article, but this causes all of the characters of the previous citation to remain as some sort of ghost placeholders and their contents be replaced by a garbled version of the citation used in the unrelated next sentence.
- [[ https://en.wikipedia.org/w/index.php?title=Kakrapar_Atomic_Power_Station&type=revision&diff=903710739&oldid=889924366 | Example 4 ]] – a citation already present in the article is cited again somewhere else, but this garbles the sentences before and after the new citation, substituting some of their letters with curly brackets, pipes and equals signs.
- [[ https://en.wikipedia.org/w/index.php?title=Herbert_L._Stoddard&type=revision&diff=904667323&oldid=900488053 | Example 5 ]]
**Expected Results:**
The citation is added or edited and no other disruptive changes are made to the markup.