Hi All,
Update: it's not broken!
I've checked all my recordings and noticed a pattern in the occurrence of the issue.
It turns out that it only happens when I start up the machine and immediately go into record.
This is fairly common when I'm walking around an interesting site to listen for nice ambiences.
Sometimes I move to a new space and I hear great sound, but the recorder wasn't on anymore.
It shuts down after a while, to save batteries. So I boot it up and start recording. That's when it
happens..
It's not a great 'feature', but in these situations the record buffer wasn't that long anyway (maybe a half second).
This accounts for the short duration of the pitched sound.
I had already sent an email to sonosax, no reply as of yet, and will sent them my findings asap.
Thanks for your replies!
Arnoud