When my BG goes over 160 for any length of time I become extra insulin-resistant, so it takes unexpectedly large over-corrections to bring my BG back down.
So my guess is that you needed more insulin for that meal, and then you needed a whole lot more once you went high. That would be why the injection didn’t work to correct the BG. The injection was a good way to get around a possible pump issue, and drinking water when high is a good technique, but my simple refrain is that if your BG is too high you need more insulin.
If the basal setting is right for this time of day (i.e., your BG stays steady if you don’t eat) then a high BG after eating might just mean you needed a bigger bolus. That could reflect a need for a change to the insulin:carb ratio, or it could be because of insulin absorption issues at that site, or it could be because of issues with the pod, or it could be any number of other factors such as infection or stress or hormones or medications.
I start to have issues with pod boluses approaching 10u, and anything above that is guaranteed to go wrong, so now I either give large meal boluses with a syringe, or I split the pod dose into a series of 5u administrations every 10 to 20 minutes, starting as preboluses and continuing until I’ve had enough, as shown by the CGM trend line. It seems that every kind of pump has its quirks, so we just get to pick what quirks we choose to live with.