Unlikely to be a cache size issue for me - I only purchased the sim a little over a month ago and have less than 100 hrs flight time.
I just completed the first 4 legs of the Carribean DR-Haiti bush trip. Only the first leg was correctly reported. Leg 2 shows a take-off & no landing. Legs 3 & 4 are missing completely. This is just 1 example. I estimate between 10-20% of my flights are not recorded at all, and a higher percentage are recorded, but with incorrect take-off and/or landing data.
[Edit: This is a basically dup of my previous comment made in another topic that was merged into this one]