Wearing Tefilin On Chol Hamoed

The Sdei Chemed writes , “The Sefer Mishna Berurah* from my friend Reb Meir Hakohen Av Bais Din Radin**, writes “It is not proper” (for some to wear Tefilin and others not to, in the same Shul  on  Chol Hamoed.)

The reason he uses the language not proper rather than Assur,

because he (M.B.) wasn’t sure if it the Issur of לא תתגודדו  . " applies   

Reb Chaim Shmuel Birnbaum zt”l writes, the first Chol Hamoed, he stayed with his father in law R. Akiva Eiger zt”l, His father in law insisted that he should  put on Tefilin, even though he (Reb Chaim Shmuel Birnbaum) came from a Chasidic background.

 Reb Akiva  Eiger held that in the land of Ashkenaz and surrounding countries , they all accepted on themselves and  on their children

"Toras Moshe" the Rema, in all his Pesakim opposing  the Bais Yosef.

* 31: sk 8

**Originally the Chofetz Chaim was Rav

In Radin, he later resigned from the Rabonus.