I wonder if they might have changed the glue because I have had some problems with them falling off. You know if you call abbott they may well replace it depending how long it was on for.
You can stick a see through patch on it - Tegaderm film is a common one and I use that.
I also use opsite flexfix, again it is a clear plastic plaster. They both work well. Both available from Amazon.
I learnt yesterday from another member that if you cover them, you must create a hole in the plaster over the hole you can se on the sensor to allow it to breath apparently. This came from Abbott.
My experience if it helps - make sure the skin is really dry when it goes on - use the provided alcohol wipe but then let that evaporate before applying. Do it when you are cool - so the evening but give it some time to "set" before you go to bed. It should stick - I have no problem with exercise or swimming or normal use. As I say - I have found just the last few the glue is not as good.
In the sun the glue does soften and that is when I find the plasters a must if you also work out or swim.