Solved (with a reasonable degree of confidence):

• DEN-SNA: another with different entries in the two halves of the table; fixed
• KUL-PEK: no plausible nearby pairs that would be about the right mileage, suspect this was a 70% fare on CA, which did exist for some time; deleted

Incorrect, pending confirmation from original posters (deleted, pending responses):

• YOW-YEG: [MENTION=194158]YZF_Elite[/MENTION]
• DEN-DFW: [MENTION=10078419]MillennialMiles[/MENTION]

Definitely wrong, but I haven't identified the root cause yet:

• FLR-LHR: definitely entered in the wrong cell, just haven't figured out where it came from yet
• LHR-VIE: off by right about 30%. Did OS have 70% earning fares at some point?
• DXB-VIE: same
• ISL-VIE: same

I spent some time looking through old Wayback Machine pages. No evidence of OS ever having 70% earning fares. Odd that three different VIE distances would be off by right around 30%, as they're probably the only Aeroplan partner that would have been flying all of those (obviously TK might have done ISL-VIE).

City pairs where we had the correct distance, but haven't figured out whence the incorrect one came:

• BKK-HKG 1172
• YYZ-TPA 1057 (typo 1097?)