I understand this isn't answering your techincial question but even if I had the answer I wouldn't understand but.
I had a look back through photo's of the arrows and graphs when I also seemed to have a similar quandry/query to yourself and as I mention before spoke to Abbott who dismiss my query.
I then did the following with arrows - no matter what the arrow said I would look at the graph and if the arrow reflected the line on the graph then great but if the arrow was horizontal but the graph was showing a rise I did some more scans soon after and if the arrow was still horizontial but the graph was on the up I knew I was actaully on a rise rather than staying level did a finger prick and make a decision to correct or leave.
I no longer use the Libre for a few reasons.
I had a look back through photo's of the arrows and graphs when I also seemed to have a similar quandry/query to yourself and as I mention before spoke to Abbott who dismiss my query.
I then did the following with arrows - no matter what the arrow said I would look at the graph and if the arrow reflected the line on the graph then great but if the arrow was horizontal but the graph was showing a rise I did some more scans soon after and if the arrow was still horizontial but the graph was on the up I knew I was actaully on a rise rather than staying level did a finger prick and make a decision to correct or leave.
I no longer use the Libre for a few reasons.