Hi all!
I also got this error when importing products. I confirm, this is due to the features field (very smart, constantina ^^).
The explanation is that Prestashop, when importing separates features with a comma. When finding a comma on one of the product features (for a text or a sentence, for example), it assumes the feature ended, and considers the text following the comma as a new feature (and by the way creates a new feature. You should have find some new features automatically created with the error, am I right or am I right? ^^)
The solution is simple:
1- Replace the comma with an commonly unused character (don't use slash /). In my case, I used backslash --> \
which means my features were written this way: feature1:name:position1\feature2:name:position2\feature3:name:position3
2- Very important: Do the same with other fields which use a comma as separator value (e.g. Category)
3- When importing your file, set "Multiple value separator" as \ (or the character you chose to use)
4- Let the show begin