It might be the original battery, but it might also be a known issue that affects some users (but not all) where any batteries put into the IKEA button die within a few days. It’s very frustrating and appears to be related to issues when the button reconnects to the network, which normally happens every hour or two.
If the problem happens to you, it is likely to persist. There’s not much you can do except try different repeaters and it seems like most people end up replacing the buttons instead.
See the following topic. It mentions a different model device in the topic name, but the same applies to the shortcut buttons
This is not a smartthings issue: you can find complaints about it in the forums for a number of different brands of hubs as well as Home Assistant. It’s an IKEA issue. but it doesn’t happen with their own gateway, so although they say they’re looking into it, not much seems to have been done. 