MC AT command answer with junk character

I use different modem (MC7304, MC7350, MC7455, MC7430…) and my application scan the state with AT commands.
I first check the RAT (AT!GETRAT?) and when connected, I check the informations with AT!GSTATUS?
The thing is that after 58 try, the modem doesn’t answer as expected with some non ASCII charactere:


and the following answer keep this format:


I tried with other commands and the only difference is the number of try before it bugs: AT needs 174, AT!BAND? needs 59, AT!GSTATUS? needs 44…
The longer the command is, the faster junk characters are comming.
I tried to change the timings, original is 1sec between each command, then with a 300ms or 10sec didn’t change the number of command before failure
Am I missing something? Is it a known issue? Is there a solution/workaround?

Forget this post, it was a tx buffer problem on my platform. (admin can delete the post)