Just going through the challengers again with Algebra and received the following error all three times when I've defeated Insight thus far:

"Warning: Invalid argument supplied for foreach() in /var/app/current/games/battle/battle.php on line 398"

Only seen it happen with Insight - unlocked with the Insight Tablet from the Millionaire Centre. The warning appears on the victory page. Nothing else is wrong with it; still received EXP and sP as expected and win count is ticking up as expected.

Yeah, I noticed this too. I don't think it appeared on win 5 but it appeared on all other wins against Insight.