[Server-side fix needed] Browsing with Tor, got CAPTCHAs for subresources

Currently using the latest version of Tor Browser (9.0), based on Firefox 68.2.0esr.

For example:
for https://www.namecheap.com/, the main site loads fine, but the pictures do not load. I went to “Inspect Element” --> “Network” Tab, and found out the pictures are stopped by 403 errors and it was a CAPTCHA page (click on a 403 resource and go to the “Response” tab). However, if I load a picture separately in a new tab, it loads perfectly without CAPTCHAs.

BTW, Cloudflare onion service has been enabled, but only the main site seems to go through onion:

alt-svc: h2="cflareub6dtu7nvs3kqmoigcjdwap2azrkx5zohb2yk7gqjkwoyotwqd.onion:443"; ma=86400; persist=1

The subresources does not seem to go through onion, since you can see the Tor exit node IP.
One example:
Cloudflare Ray ID: 52a9010a48849e0d
Your IP: 185.4.x.x (Some Tor exit node IP)

This is just one example for Namecheap. Multiple websites have this issue. Please fix.

Someone opened a issue in the Tor bug tracker.

I changed the header to */* for a test and got no more CAPTCHAs. However, it’s not recommended to change the header in Tor Browser. Please fix at the server side.