I want to make sure you're able to edit your recurring transactions.
Our Support Team has not communicated any ongoing issues related to the error message you're getting when editing a recurring transaction in QuickBooks Online. In the meantime, let's try performing some troubleshooting steps to get past the problem.
You can create a new recurring transaction that's similar to the item you're trying to modify and see if it gives you the same problem. If it does, I'd suggest switching to a different browser or a private window. Doing this will help us isolate if the issue is caused by the large data on your cache. Here's how to switch to a new window:
Google Chrome: press Ctrl + Shift + N Mozilla Firefox: press Ctrl + Shift + P Internet Explorer: press Ctrl + Shift + P Safari: press Command + Shift + N