TYPO3 Core

Happend in the list module. We have objects with multiple inline references. Translations were triggered in the list module over the 'localize to' option. If only one translation is triggered at once, everything translates like it should. However, as the buttons for the different language are right beside each other, some users will click multiple flag-buttons at once and thus trigger multiple translations at once. If that happends the inline references inside the triggered translation will be messed up. There will be multiple duplicated translated inline references and the l10n_parent will be faulty too. In our instance it happend that they all referenced each other and were hard to clean up that way.
E.g. Main object A has inline object B. Translation for A is triggered for multiple languages at once. The translation will look like: translated Object A has now multiple translations of object B (we call them B1, B2, B3). B1 will point at B in the original language for l10n_parent, while B2 will point at B1, and B3 will point at B2 as l10n_parent. This makes it hard to clean them up via the database, but wouldn't be nessesary if there weren't any duplicates to begin with.

The easiest solution would be to maybe disable the other language buttons once one translation is triggered or check if there is already a translation process running and prevent the system from doing multiple translations at once. After a few seconds the translation dialouge will open, but by then an impatient user will already have clicked multiple translation buttons.