i could be wrong on this - i hear that all the latest ..well last 15 years have inductive charging of the keyfob, meaning it has a rechargeable battery in the keyfob, looks like on yours maybe the rechargeable battery has reached the end of its life , and is hanging on .
That's if it has a fob ..as you don't state year, for any other questions you ask here, at the least we need engine size , and year.
Sorry it's a 2014 2.2. I replaced the rechargeable battery a few weeks ago and it was working fine once it had charged up. I've also checked the remote out of the van with my RF meter.
Had a look on forscan and amazed to see battery age in days. They are 4030 and 4056 respectively which I reckon is 11 years so new ones on order. I guess there is some sort of timer module built into the battery.