Hey @Kasia5 , you've posted this question in the SPM forum, when in fact this is a wider platform issue, but I'm happy to have a stab and see if I can help.
Portal widgets and Portal Widget Instances can be slightly confusing when promoted between instances. I recommend looking at both pages in the Page Designer. It's likely that your update set has either duplicated or failed to update an element during the promotion.
There are a number of ways you can address this, but there may be a use case for making the required update in the target instance (within an approved change window where appropriate) as the easiest fix, then making sure your cloning schedule is up-to-date so that this is synched back to the previous instances afterwards.
If my answer hasn't helped, or even if you just fancy getting a wider range of specialist opinions, it may help to re-post this question in the Employee Center forum.
