This makes me think 1 of 3 explanations is the real reason behind this:

1. They really underestimated Russia and thought they were too low on missiles or no longer had the capacity for this kind of attack

2. They lost the people that knew what they were doing (either dead, injured or dealing with shit in a very vital area) and idiots allowed this to happen

3. It's a smokescreen, they sold the weapons to other 'unknown' third parties and set it up so these places would blow up covering their tracks.