Taking a look at what Pyrex is available, Germany has the same "PYREX" versus "pyrex"problem. About 10 years ago private equity bought Pyrex and changed the glass formula which caused moderate temperature variation to break the glass. Think boiling temp to ambient temps.
The thing to look for is the logo. Before the buyout. Pyrex used all lowercase letters. After the buyout the logo changed to all capital letters. Lower case is the classic high durability pyrex.