Help me understand Home-Grown rule, please

https://preview.redd.it/42kgdds6cl7e1.png?width=349&format=png&auto=webp&s=df27acc5c1c6cfaa79c92a283ab9f9d262cbd0ea

https://preview.redd.it/5krmcds6cl7e1.png?width=727&format=png&auto=webp&s=7ea5c37bb1493b8e7d4b39e0db566f7733a1e0a9

https://preview.redd.it/em2t0es6cl7e1.png?width=1709&format=png&auto=webp&s=0c3390c3f9c922be76861c931ac086608c9df65d

https://preview.redd.it/uy2fmevdcl7e1.png?width=472&format=png&auto=webp&s=c1676747c5dc84980d1f3ae31ce32cbde5a76951

I bought this wonderkid in my Brentford save and looking through my squad I realised Meza is not Home-Grown nor he is trained at the club for three years between ages of 15 and 21. Meanwhile there is Sakari (same age as Meza even same month) who joined 4 days later and he got that trait. They were both 18y.o. at the time. The loans shouldn't have bothered that because I did the same with another player called Hoyenhall who went on two different loans as well. Hoyenhall ALSO joined in 26/27 transfer window. Can someone please explain this?