Google Optimize for A/B test: Trying to edit existing HTML but says it’s over the limit even when I test deleting some of it?

I am trying to set up an A/B test of a company’s website for my project. There are certain changes I’d like to make such as changing the ‘favourites’ products on the home page to one with the top selling products which I was trying to do by substituting the existing code simply with the top selling products instead (i.e. their jpg, their links, their names etc).

However I found that when making ANY change (by selecting the element and clicking ‘edit HTML’), even testing it by deleting one character from the original code, that it then pops up with this error notification saying that it’s over the word limit. Even when I put the character back for example, the error message is still there. And it will say weirdly that it is quite a lot of the word limit even though it’s basically the original code! I then have to click cancel every time.

Please see the attached photo for reference (where I deleted one character from the original code to demonstrate how any editing (even deletion of original working code) then comes up with the error that the html is over the limit).

View post on imgur.com

Thanks in advance!