Ever feel like you’re pumping insulin and it’s having no effect?

So Glad I stumbled across this website. This is my initial post and I am in need of some input or direction. I have been on an insulin pump now for 15 years. I am currently using the Medtronic Paradigm 512. I have had 3 periods over the past 1.5 years where I am having nearly continual high readings. It feels like I am injecting insulin that has gone bad. This is especially true overnight. The second time this occurred I figured out I, in fact, had an entire batch of bad insulin. This time I am stumped. I have doing a lot of troubleshooting including the following:

1) Called Medtronic and put the pump through 45 minutes of testing. Pump did fine. It is supposedly working. Also I noticed all along that Insulin is coming out of the Silhouette setting tubing when I disconnect and do a fixed prime or a bolus.

2) Changed infusion sets, cartridges and sites multiple times and made sure to use an unused site several times.

3) Got new Novalog insulin from a different pharmacy and put it in the pump.

Last night, out of sheer desperation and with a BS of 351, I changed my insulin and put in some older (but not expired) Humalog (instead of Novalog) insulin. Today has been better, however, I have not gotten through the night yet.

I am wondering two things: 1) Can it be that the Novalog breaks down in my pump after about 12-24 hours while the Humalog does not? My insurance co made me switch from Humalog to Novalog. 2) Am I digesting my dinner overnight? I have gastroparesis. Would this explain the nighttime highs and does this happen to anyone else? Any advice, suggestions or feedback from the pump pros would be much appreciated. I feel like I am the only person in the world this has happened to when I speak with the pump company or my current lackluster endocrinologist. I have set up an appt at the Joselin Center in Baltimore for the end of January.