The research into last year's flu season puts the blame on egg-based vaccine production.
Reference:
https://www.vox.com/science-and-health/2018/2/1/16960758/flu-vaccine-effectiveness
Researchers guess at the dominant flu strains well before flu season starts, then grow the strains in chicken eggs - an outdated process that takes weeks.
Additionally, H3N2 (influenza A and the dominant strain last year) is infamous for rapid mutation. Often, the dominant strain can mutate after the previously mentioned researchers' guess has been finalized and the vaccine is queued for mass production. Also reported in the Vox article: 33% combined vaccine effectiveness in H3N2 seasons, vs. slightly over 50% when influenza B dominated and 67% in H1N1 (swine flu) seasons.
Another problem the article mentions with growing flu vaccines in chicken eggs: H3N2 viruses mutate to get better at infecting the eggs, which means that even if you guess at the correct strain and grow it in eggs, the output vaccine isn't guaranteed to have the same structure (and therefore won't be as effective as expected).
Why is the industry still using eggs?
2 reasons, again mentioned in the Vox article: The industry is already optimized and built around the egg-based workflow (economy of scale) - and more modern approaches (cell-based and recombinant) are far more expensive. Additionally, more research is needed to determining if the cell-based and recombinant approaches produce a more reliable vaccine.
In a summary answer to your question, it would appear to be "no", due to the egg-based mutation mentioned above. The Vox article also mentions abysmal protection rates in that season's vaccine against the dominant H3N2 strain, as low as 17% reported in Canada.
