Yes. My instinct is that it was a result of running Linux as it is likely the majority of spam requests come from Linux servers whereas the majority of legitim

Yes. My instinct is that it was a result of running Linux as it is likely the majority of spam requests come from Linux servers whereas the majority of legitimate requests come from Windows computers. It makes sense that anti-spam systems would take this into account. To fix this I changed my browser fingerprint to tell websites I was running Windows. I have no data to prove it, but I feel as though this has reduced the number of CAPTCHAs I've had to complete. Also, it is possible websites are increasing their anti-spam measures as a result of the alleged Russian interference in the politics of western countries using bot/spam accounts. My final theory is that someone is paying them a lot of money for the data they collect for use in training their self-driving vehicle AI. In this case they would want to show you CAPTCHAs more frequently to collect more data to sell for more profit.