No, I have many channels set for a different audio track and they are all remembered.
Check the BLUE/BLUE panel, the "Auto language settings".
Maybe you enabled some option like, for instance, "Prefer AC3+ track". And, I assume the "Prefer audio track stored by service" is ON.
Actually, this option sounds odd in the original English form, because it seems the opposite of wanting OUR choice to be remembered.
But if you look at the option description, it says the right thing:
"When enabled, the receiver will automatically use the audio track which you selected before"
In the Italian translation
@insanity and I set it much more clear