I haven't seen this before. Do you have a reference link?
There is no reliable sources for any data which is affecting national security during war times! Not to mention that there are already enough protests around Europe.
It is a simple analysis: Where did Germany get that much gas to fill the storages? It's a matter of supply and consumption, there is significantly decreased supply + slightly decreased consumption; so there is definitely no excess gas to be added to storage.
1. Russia significantly decreased the gas exports very early in the war (down to 40% and 20% exports to EU and they even recently shut down Nord Stream I which is completely removing part of that export).
2. Germany hasn't been able to secure other sources either.
2.1. US hasn't fulfilled the promises and they even created 2 fake explosions in their LNG ports which aren't going to be fixed this year (they needed to dump that gas domestically to keep the price down inside US and save their own economy).
2.2. No success with Canada (they keep saying they can send LNG but they haven't yet!)
2.3. Qatar, Iraq, other Arabs haven't been able to increase their production to send anything major to Europe let alone to Germany. Not to mention they already have other customers elsewhere that have increased their own demands.
2.4. Iran with one of the biggest gas reserves isn't going to send anything (oil or gas) towards EU any time soon
2.5. Turkey (a lot of gas was going through it towards Europe) is being greedy and wants to get gas for $350 then resell it to Europe for $4200 so at least 14 billion cubic meter (that's the confirmed amount which could be higher) export to Turkey was halted.
3. For the very little gas left in the global market, there is a lot of demand elsewhere specially in other parts of Europe, not much is left for Germany.
4. Germany does't have the capability to go in another country and either steal their gas or force them to give it to them like what Brits and French have been doing over the past couple of months in North African and West Asia.
The best case scenario is that they haven't yet touched the stockpiles and the storages are a little less than half full. If you add the amount US
promised to send (but hasn't yet) to this amount you get to about 85%.
This is one of the contributing factors to Uniper needing $19 billion bailout money.