OK, this may not mean anything, but "Forbidden" seems interesting to me 
. I ran tcpdump on the OpenWrt side, watching the LuCI (Port 80) traffic, then looked at it in Wireshark. Thoughts?
GET / HTTP/1.1
Host: 192.168.250.1
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
If-None-Match: "64d-20a-6128f525"
If-Modified-Since: Fri, 27 Aug 2021 14:22:29 GMT
HTTP/1.1 304 Not Modified
Connection: Keep-Alive
Keep-Alive: timeout=20
ETag: "64d-20a-6128f525"
Last-Modified: Fri, 27 Aug 2021 14:22:29 GMT
Date: Sat, 28 Aug 2021 03:52:07 GMT
GET /cgi-bin/luci/ HTTP/1.1
Host: 192.168.250.1
Connection: keep-alive
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.250.1/
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
HTTP/1.1 403 Forbidden
Connection: Keep-Alive
Transfer-Encoding: chunked
Keep-Alive: timeout=20
X-LuCI-Login-Required: yes
Content-Type: text/html; charset=UTF-8
Cache-Control: no-cache
Expires: 0
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
Thanks!