Cannot translate a specific string

Hello, I’m trying to translate some of the strings to Spanish and cant seem to make it change. I have translated other strings (saved, add to bundle) using loco translate but for some reason this particular string wont change even though I can see it on the list of available phrases to translate.
The one giving me issues is: Please select products for all items of the bundle.
I have tried clearing cache, etc, but it simply wont change. Any ideas? Thanks!
p.s: this is a live site.