NDB identifier on a320

[qwsa]

Hi there!
I've got one question. The navigation display on the a320 shows ident letters of the NDB.It shows two letters usually,but sometims it shows four letters...For example:
"FRFR" instead of "FR"
Do you know why it happens?I've read lots of papers,but still don't have answer.
Thanks.

[autoflight]

Many years ago I think I also saw this type of double NDB ident on an A320. Possibly the decode word space is set too long and if the FR NDB ident space is set too short, result can be confused. There might be an absolute max of 4 characters, which would explain why the ident was not just continuous FRFRFRFRFRFR etc.

All that is mostly a guess.