Looks like someone stirred up the hornet’s nest. Poland’s Russian gas contracts were for renewal the end of December but were canceled in May when Russia needed to be paid in rubles because they were kicked out of SWIFT? Terms of payment needed to be changed which is a condition usually spelled out in any contract. Evidently Poland had a long term goal of exiting the Russian gas market plus eliminating the entire EU from it.
Who stands to gain by blowing up a pipeline?