dragonfly
No it isn't common for this to happen,,,
If you are using humalog insulin, get a new supply in as there has been on batch number, which apparently been causing problems something to do with storing issues within the chain, the batch as been recalled from suppliers... I see if I can find the batch number for you and pm it if I can..
Another area to look at, is check the batch number of your sets and use a different batch no if possible, sometimes set's can cause problems as in the batch is duff, not just a single set..
As I said it's not that common most pumpers once they've pinned down their basal etc, will only get a slight movement and just need to tweak basal once in a while, hence the need for regualr basal testing..
If you feel that your basal does need changing, first consider is your control being affected by more than normal stress or perhaps you are coming down with something both these can wack up insulin needs..
Sometimes it pays to hold off from making changes to your basal profile for a week or so and use the TBR until you know that this is a sort of perment change and not something caused by an underlying glitch such as stress, illness etc..
A tip
When you aren't 100% sure if it's a change of needs etc, set up another profile with your current profile and make adjustments to this profile, so if it is a glitch you always have your orginal profile to return to! It's a good idea to always to this if you'll adusting the basal profile, then when you've worked out the correct setting swap this to your old profile..