Line 17: 2019-05-29 16:17:23 (622 KB/s) - Read error at byte 1931163840/3871913592 (Connection timed out). Retrying.
Also, would an ack line be better at this job? And if so, what/how?
Wrt I assume the problem could be the /s or ---s or >s or ==>s or |s? - no, there's nothing special about any of those characters/strings. It sounds like you might have DOS line endings (\r\n), see Why does my tool output overwrite itself and how do I fix it?. Since you said with cat logfileA.txt, all I get is the last line which is garbled I wonder if you ONLY have \rs and no \ns as line endings. If you do then tr '\r' '\n' < logfileA.txt > tmp && mv tmp logfileA.txt would fix that. If that IS the issue then going forward you can use awk -v RS='\r' 'script' to change the record separator from it's default \n to \r and then you won't need to do that tr step.
You don't need grep when you're using awk though. This: