You'd think that the little springs would push the saddles along, but the tension of the strings is greater, and they jam where they are. Lever them along, or tap them gently - it's better than slackening them each time, as you can check the intonation straight away. Of course they're going to be out of tune, but for intonation checks it doesn't matter.
Now may also be a good time to address the age old problem of the 1st and 2nd string saddles never being level with each other,(2nd string is generally a little longer than the 1st) thus leading to a compromised intonation there. I filed my (brass) saddle so that the 2nd string was effectively longer than the 1st, sloping it in opposite directions for each. Voila - good intonation available!