Hello. Something similar happened to me today. Yesterday, Construct 2 was previewing my game in Chrome just fine. Today, without making any changes whatsoever to the project, every object that had the "glow" effect in the layout turned invisible! I checked older versions of my project (I have a weekly backup) to see if it had been something I had done wrong on my latest version... But ALL of the versions now share this problem. Deleting the "glow" effects of the object didn't seem to work either, now they're always invisible. I've only been using Chrome for these tests. Maybe it's the browser that's not rendering the glowing objects correctly?
(This only happened to me today. I've been using construct almost every day for the last 6 months, and had never seen this issue).
Any help or advice would be greatly appreciated, as I was just a tweak or two away from finishing my project, and it was meant to be used as my official Game Design portfolio to find a job in the industry. (I recently graduated as a Game Designer from College).