If you could data log that signal it would be useful for determining if that's the issue.

there are three lines to the pickup, not sure what they are. B+, GND and SIG?

If you could data log the B+ and SIG, make sure you aren't losing power to it.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.