Same here starting about 7:44 GMT+1 . As a workaround I use this script to get a good response in to a file and use it whit ssl_stapling_file directive in nginx. The script is only part of the script posted by @Troon here
#!/bin/sh
SITE=$1
LEDIR=/etc/letsencrypt/live
DIR=$LEDIR/$SITE
HOST=ocsp.int-x3.letsencrypt.org
MTO=my-email@example.com
openssl ocsp -no_nonce \
-respout $DIR/ocsp.resp.new \
-issuer $DIR/chain.pem \
-verify_other $DIR/chain.pem \
-cert $DIR/cert.pem \
-url http://$HOST/ \
-header "HOST" "$HOST" > $DIR/ocsp-reply.txt 2>&1
if grep -q ": good" $DIR/ocsp-reply.txt; then
if cmp -s $DIR/ocsp.resp.new $DIR/ocsp.resp; then
rm $DIR/ocsp.resp.new
fi
fi