Full training boosts aren't realized until foal training is complete. From the wiki:

"Foal training is used to unlock your foal’s training boost (TB). Every foal will have 1 TB or 30% of their TB unlocked naturally, whichever is higher. Each foal training session adds 1 TB or 10%  of possible TB rounded down, whichever is higher. All training steps round down with the last training completing the remaining TB to be earned. Foals that do not complete foal training cannot earn their training boost later, therefore it is highly encouraged to do your foal training."

foal TB is also dependent on parent's levels at time of breeding, if their levels were low then the foal TB will also be low. foal TB is parents levels added together and divided by 10, it's recommended to breed horses after they reach level 50 since 50 + 50 = 10 TB. you can of course achieve a foal TB of 10 with other combos like 30 + 70 or 40 + 60 and so on.

Well that's the weird thing.

One foal's parents are level 44 and 45. She only has 2TB, which is what she started with when she was born. Her final training should be ending soon.

i don't see anything wrong with their TBs, two 8s and a 9 look about right

Oh really? I only see 2. must be a glitch for me.

I see three, two 8s and a 9. Like @forgottenland said, that looks normal.

Totally random, but are you looking in the right location? If it really shows 2 for you, you could report it but it would be weird since we all see two 8s and a 9

are you able to take a screenshot of how it looks from your end? this is what the first foal looks like for me.