Weird problem - NOT recording

hello.

I'm currently (now) recording 2 x movies on TIVO. This is good.

I've watched one (separate) movie which was/is set to NOT DELETE.

i want to change it so it deletes / expires in a week, and tivo advises it will; NOT record (or stop recording) one of the two movies its currently recording - due to insufficient disk space. I'll wait till it stops recording & then change the settings of my movie ive just watched.

ISSUE - if i have a programme that is set to not delete, & then change it to expire - would this not free up MORE space (& in theory delete programmes earlier ?)

why would it stop the currently-recording movie ?

Is this fixable ? (re-programme of TIVO programme & then upgrade the next time a person connects to the tovo EPG etc..)

PS, I'm in NZ.

EDIT: 1 of the movies has now finished, & i was able to edit my older movie to delete in a week. Must bea n error when recording 2 shows at a time ??

EDIT: version 11.3b6-01-2-663