Are you talking about a bottle of insulin that you've been using for a while, or a fresh bottle? Hard to tell without that info what's going on.
As a long-time Type 1, you've probably got waaayy more experience than I do, but a couple of thoughts occurred to me:
1. Are you getting your insulin via mail-order pharmacy? Sometimes their shipping parameters aren't all that great.
2. It sounds like you're on the pump. Perhaps you may need to use less in the reservoir and change it more often?
3. Do you keep the unused bottle in the fridge? If it's really hot, that may help the unused insulin stay fresher.
4. Do you work outside? The pump reservoir may indeed be overheating if you work outside. Again, perhaps changing more frequently might help?
5. If the insulin seems to be failing as soon as you start using it, ask the pharmacy to replace it, as possibly they got a bad batch or they didn't store it correctly.
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Old new guy 
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