Is it still happening?

I suppose that you managed to delete the first one (Кашира), but the second one fails.

@Nikerabbit can't delete [[Róisín Murphy]].

I can't delete [[Gestapo]] (en->es) and [[Garvan Point]] (nn->no). I created both to test bugs :/

The issue here is, while testing some issues, same title will be used by more than one person. Ofcourse the second person use that title only after the translator either discard or publish the title. The delete API check the 'translation_started_by' field to verify the translation belong to the user trying to delete it. That will fail in the case of second translator and cannot delete the translation.

The fix I have in mind is:

diff --git a/api/ApiContentTranslationDelete.php b/api/ApiContentTranslationDelete.php
index d8a0da2..75ffdbe 100644
--- a/api/ApiContentTranslationDelete.php
+++ b/api/ApiContentTranslationDelete.php
@@ -25,7 +25,7 @@ class ApiContentTranslationDelete extends ApiBase {
                $translation = $translation->translation;
                $translationId = $translation['id'];
                if ( $translationId === null ||
-                       $translator->getGlobalUserId() !== intval( $translation['startedTranslator'] ) ) {
+                       $translator->getGlobalUserId() !== intval( $translation['lastUpdatedTranslator'] ) ) {
                        // Translation does not exist or belong to another translator
                        $this->dieUsageMsg( array( 'invalidtitle', $params['sourcetitle'] ) );
                }

Change 242053 had a related patch set uploaded (by Santhosh):
Discard draft: Validate against last updated translator

https://gerrit.wikimedia.org/r/242053

Change 242053 merged by jenkins-bot:
Discard draft: Validate against last updated translator

https://gerrit.wikimedia.org/r/242053