There are multiple reports on de.wikipedia, that the "mw-disambig" class sometimes is missing on links to disambiguation pages.
Examples:
* https://de.wikipedia.org/w/index.php?title=T%C3%BCrfeststeller&oldid=151577534 (link to "Bolzen")
* https://de.wikipedia.org/wiki/Wikipedia:Fragen_zur_Wikipedia#Der_Begriffskl.C3.A4rungs-Check_hat_einen_Aussetzer
* https://de.wikipedia.org/wiki/MediaWiki_Diskussion:Gadget-bkl-check.js (links "Aal" and "Abklatsch" at the very bottom)
* https://de.wikipedia.org/wiki/Barbados_%28Band%29 (link to "Barbados (Begriffsklärung)"), while in https://de.wikipedia.org/wiki/Barbados the class is present for the same link
Purging the pages does not fix it, even with "forcelinkupdate". In preview, the class sometimes is present, sometimes it is not.
Latest code changes are {rEDISbc99c458cf8eb48df729021b20e0a71f4ac643ed} and {rEDIS3fad1145b598e49135d3dc209d52df880ee33cf8}