Click Rate & Click to Open Rate decreased overnight in Mid-Feb

Are you able to verify whether your Admin has turned on the bot filtering feature (or enabled additional filtering options available within it) in your Marketo instance due to which you’re seeing lesser email clicks and open rates? I’m sure Marketo would let users know prior to making such drastic changes to the email performance report.

As @darshil_shah1 said, definitely check with your admin on whether or not you're using filtering or logging bot activity.  Also,  be cautious with CTO -- as opens can be unreliable due to MPP or image prefetching, you could be factoring in opens from people who never truly opened your email.

Some things to check:

--Have you verified that no filters were accidentally added to your performance report? If you're not the only one who has access to the report, check to make sure there isn't anything being filtered out at the report level.

--Is there someone (or a group of people) who engaged during the first timeframe but not in the second? Can you identify any characteristics that link these folks? If you're filtering bot activity (but not logging it), there's always the possibility that something about these contacts was flagged as a bot and thus removed

Keep in mind that there are still variables in play here -- you're sending during a different timeframe. While an 80% drop is pretty unusual, consider that there might be something that changed about your audience based on sending during this timeframe.  Do you have a Y/Y comparison to look back to? It's always important to factor in potential seasonality. 

We've experienced the exact same thing - drastic drop in mid Feb of both opens and clicks. In my case, I am the admin and did not make any changes to the bot activity filtering settings.

We have noticed the same issue and have an open ticket with Marketo Support and awaiting an answer. Feels like a large number of bots were identified and added to the filter or something is going on with the click tracking.

Hi, we had the exact same problem, with even more drastic decreases, and got the exact same response from Marketo Support

This is a significant problem and from what I've been told, Marketo will soon be releasing a statement on this. Here are my thoughts on this: 

• This is NOT bot related. We're seeing the same 80% decline in click results and while I can't say for sure that we do not have some bots in our database, they certainly are NOT generating 80% of our clicks. We have over 5 years of historical click data in multiple marketing platforms that supports the point that the decline in clicks is completely inaccurate and overstated. So the support suggestion that there are a handful of problematic IP addresses is just wrong, and it's troubling that support is completely out of the loop on what is happening. 
• For Marketo customers who are deploying emails on behalf of our customers who are paying us, this is a tremendous problem and we do not have a usable explanation from Marketo. This is really bad. 
• What seems most likely is that Marketo is suppressing corporate security software that is preliminary testing emails by clicking on all of the links in an email; I am ok with this, however from what I've been told Marketo is then suppressing ALL subsequent clicks from that company. So for example, if company XYZ scans an email through software for security purposes, determines that the email is safe and then delivers that email to 100 people within that company, and some of those people click the email, those clicks are being suppressed in reporting. 

We've been dealing with this for nearly 2 months and it's very disappointing that Marketo has not fixed this and doesn't seem to have a logical understanding of what is happening.