A few quotes from the Rabbi on 'Customs of Israel'
in which he instructs that the custom, in this Ashkenazi tradition, is not to be considered as a rule, because they were under domination
Despite the fact that to date it has not been customary to perform marriages during the bein ha'metzarim period among Sephardim and among 'Edot HaMizrach as well, I have instructed that leniency be applied from now on…
I have heard that there are some who protest my approach, saying that since the Chief Rabbis of Tel Aviv-Yaffo who set stringency as the norm preceded me, the custom should not be changed, and that this is not a matter I have the have authority to oppose. It is, in any case, a known fact that the Sephardi Chief Rabbis preceding me were dominated by their colleagues, the Ashkenazi Chief Rabbis…who were in charge and controlled those rabbis who perform marriages, and imposed Ashkenazi custom everywhere. They remained silent for the sake of peace, ministers refrained from speaking, "Nobles held back their words; They clapped their hands to their mouths". These things are clear and public knowledge. In such a case, it is certainly not to be considered a custom…and for us, who are not dominated, praise the LORD, I will stand guard to reinstate the glory of the past, and instruct in keeping with the opinion of Maran [our master] whose teachings we have accepted.
Yabi'a Omer Responsa, Part 6 – Orakh Haim, Section 43, p. 142, Jerusalem, 1976