I have multiple websites with C5 and I am getting an error message whenever I try and save an edit to a block. This is only happening in Chrome and started about a week ago. Safari works fine. Attached is a screenshot of one of these errors. If I close the error box and reload the page the change does take effect. So technically I am able to make edits using Chrome but I get the error message every time I hit the Save button.

I don't believe this is an issue with the website because it is happening to multiple websites.

I am on a Mac running 10.10.2
Chrome 40.0.2214.94 (64-bit)

For the C5 site in the screenshot it's 5.6.2.1

Any thoughts on what is happening?

Thanks.