Is it only SOME info from a match that fails to get saved? That is, does birthdate get saved, but marriage date doesn't?
Are you sure that the new info is actually marked as 'new' or 'improved' or 'different'?
If you have a mach that offers a green SAVE TO TREE button at the top-right, any info that's new or 'improved' than your info, will be copied over. That info is marked with a little red text box beside each field on the other individual.
**NOTE - there can be other info in that person's profile that you WANT to copy over, but isn't marked as 'new' or 'improved' - it won't copy over unless you EXTRACT the details manually.
When you have the choice to CONFIRM (red button top-right) a match, it just makes a connection between the individuals in their tree and your tree. It doesn't save any details to your individual. This would happen if the system doesn't see anything that's better than what you already have.
If there's a down-arrow on the right of the CONFIRM box, it is telling you there is data that can be copied over, but you need to drop-down that arrow and click on the SAVE TO TREE. That info is marked with a little red text box beside each field on the other individual.
If you are EXTRACTING details (in the long, detailed info boxes), you need to click the left-arrows down the middle, to copy that section of data to your individual. Only when those arrows are bright-green, is that info going to be copied. The info on your person (on the left) should change to show what it will become.