I think it’s intended. As if you try to peel bark in fall/winter the game prompts: “It is not possible to peel bark at this time of the year.
The best season for harvesting bark is early summer”
That bit in gray to me indicates it’s intended feature. If you peel bark with spring start, you’ll get 60-80’ lengths, then from Seedtime/Fallow you get up to 110’ (I think), and it’ll diminish to 50’ by Harvest. Fall, you likely won’t get any.