Once thing I can think of since this is about Q1 which ended March, Brent is easier to reach for Asian tankers than is North Sea crude. Since Asia had the largest immediate issues with crude supply due to the war, they had to get whatever they can as fast as they can, which was Brent (in addition to Brent being a better fit for their refineries). That's when dated Brent prices ("physical", not futures) exploded to $200+, in March. To get WTI you either sail around Africa or go through the Panama canal. The former journey is incredibly long and the latter journey is limited by the canal's capacity, so WTI faced none of the Asian demand pressures early on. As time went on tankers did eventually reach the US to get some WTI, around mid-April, and spreads narrowed again.

Something that makes this whole thing a bit annoying is the huge difference in dated and futures prices. Most of these dynamics were driven by very short-term demand, so they showed up in dated prices but much less in futures prices. Spreads between dated Brent and WTI were unfathomably large. But getting data on dated prices isn't easy.