The phrase "previously during" is grammatically correct and can be used in written English.
It means that something happened in the past during a specific time period. Example: Previously during my trip to Paris, I visited the Eiffel Tower.
Trump has stated previously during the campaign that Seoul should pay more for its own defense.
Mr. Gore said little in the 90-minute session that he had not said previously during the campaign.
Previously, (during exam week) the large electric machines had been brought into Phillips Hall and permanently wired.
Previously, during the countdown, time slowed to a surreal crawl, but now it seems to be racing forward, to the moment of Oppenheimer's death.
The ECB added: "The pair had contravened their conduct obligations previously during the tour and had been issued with written warnings".
I understand that -- I think he was pained and angered from what had happened previously, during the first stage of this controversy.
Lineage replacement seems to be a common phenomenon in YFV genotype I evolution, as was observed previously during the replacement of the Old Pará lineages after the 1960s12.
Many manic-depressive subjects report turning over in their minds all the bad things they have done, even years previously, during their lows.
Previously, during his dive off Papua New Guinea, he had lost use of one of the submersible's 12 thrusters.
Previously, during his twenty-four year government career, Armacost served, among other positions, as undersecretary of state for political affairs and as ambassador to Japan and the Philippines.
The alloy formation phenomena observed previously during Cd UPD on massive Ag electrodes were found also in the case of Cd UPD on Ag nanoparticles.
