I am confused (a state my friends and others may confirm is not unusual).

OLC rejects flights from secure flight recorders where the validity fails
(for example, where the internal battery which backs up the security
number has gone flat).

Are you saying that IGC files from non-secure recorders, such as PDAs
which can be driven from GPS which

(a) are not necessarily set to WGS84 and

(b) may have the 'prediction vector' enabled - this can record a
position in a zone when the glider turns outside

are acceptable, but one from an IGC approved recorder are not unless they
pass the validity check?

If so, bizarre.