

It’s not immediately a DNS issue. Usually if there’s no response within less then a second, then a browser will skip IPv6 and use IPv4 (Happy Eyeballs). But in this case the server responds with an SSL error over IPv6.
curl -v -6 "https://rebeltechalliance.org/"
* Host rebeltechalliance.org:443 was resolved.
* IPv6: 2a10:e000:1::10
* IPv4: (none)
* Trying [2a10:e000:1::10]:443...
* ALPN: curl offers h2,http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* CAfile: /data/data/com.termux/files/usr/etc/tls/cert.pem
* CApath: /data/data/com.termux/files/usr/etc/tls/certs
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLS connect error: error:00000000:lib(0)::reason(0)
* OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to rebeltechalliance.org:443
* closing connection #0
curl: (35) TLS connect error: error:00000000:lib(0)::reason(0)
It’s weird to do this daily, but it’s possible that the UPS is doing a self test, which would drain the battery a little and the load is from charging it back up.