Enigma was cracked many times, because Enigma changed, there were many versions, and more importantly procedures of using Enigma were different in different German army branches.
Poles first cracked only some versions, and only if Enigma was misused (which was common because it was convenient), then they improved the method, cracking more difficult version, and making the method more general.
Poles also built the first machine to crack Enigma (functionaly it was many enigma clones connected to each other, trying many keys at once basing on some assumptions to reduce the search space).
Then Poles sent that knowledge to French and British just before WW2, and British developed more general method, and built better cracking device.
British contribution was important too, it made cracking more versions and Enigmas used with better practices possible. But yes - it was outrageus that they pretended for decades it was they that solved the Enigma in the first place and said nothing about Polish contribution.
And the Hollywood movie was even worse propaganda, and it was created recently, when the archives weren't secret, so they don't have any excuse to show lies.