There are three ways to solve this issue:
Enable SATC Bar button from APP backstage again and hard refresh merchant product pages to check if can display SATC Bar properly or not;
If SATC Bar is not showing still after enabling APP button again, please help check if merchant website can load our APP JS code properly or not.The way to check whether JS is loading or not is to press F12 and then select Network this column, choose the filter as JS and then input keyword "sticky" in the search blank. After that, reload this page and see if our APP JS result is displaying or not. If JS result can display propery and the status is correct, then it is mostly related with brower cache or APP switch as well as settings, we can solve it with method 1 here.
3. If we fail to search out any JS results about sticky cart from inspection page, then our APP is not injecting related code properly on merchant website. We need to check whether merchant switched off our APP Embeds block button or not before. If so, we need to ask for access from merchant end and click Customize button via theme from Shopify backstage and access extensions to check whether our APP Embeds block switch is enabled or not. If it is not enabed, please enable again and click Save button. Then hard refresh merchant website page to check if SATC Bar can display or not. If can display normally, then this issue is gone here.
Note: Related issues like Quick Buy/Sticky Cart not showing can also follow the three methods shared above. If all of them are not working while checking on your end, please make sure collect related merchant issue details and leave a note of what you inspected, then escalate to my end directly.
After inspecting again on my end, I will escalate to backend developer end directly and solve this issue from APP Team Database.