The whole childhood forgetto memory thing is too common in jp works recently, and here it was very unnecessary when the flower field meeting is good enough to work on its own.
And it's memey because the mc usually conveniently has his memories, uhh, "remembered" at the same percentage as the romance subplot progression.
The price u pay for getting a childhood reunion story that way is a copout, it renders most of the story development meaningless because the reason for marriage is now mostly "we got kindergarten crush memories back".
That weak writing point is not really related to trope use per se. A vanilla flower field meeting is also a trope.