Welcome Laurent,
Pocketsphinx and Flite have some little leaks (not big enough to create a problem even over weeks of use IIRC) so the sample app always shows a few leaks. But it’s possible that there could be a new leak introduced with 2.5 – if you’d like me to check it out, I’d need to know what you saw in Instruments that makes you think it originates with OpenEars, which means the names of the objects and their object sizes that Instruments reports as leaking, thanks. Best is to get a report like “after one minute of operation which included starting listening and stopping listening, Leaks reported a leaked object named __ of size __ and the total size of the leaks for object __ over that time period was ___MB.” And let me know what you did in that timeframe so I can attempt to replicate it and see the same thing.