Post exercise highs

I know this has been done but i was wondering if i could get some help. This is starting to happen on occasion for me and because its not routine its annoying.
2 days ago i did a 300 swim and 4km worth of intervals (running). i started with bs 9mmols and finished at 6. So perfect.
This morning i did a 10km run. I ate half a cup of oats and didnt bolus and ran my sugars up to 9mmols again. About 5 kms into it i was feeling a little bit doughy and checked and i was 4.8. Not too bad but it is a very hot day and i have a cold so i had 3 energy chews. I kept running and a decent click and checked towards the end of my run and i was 6.8. I finished soon after and figured my bs would have dropped to maybe 5 or 6 even and would prob drop further so i had my usual post workout banana. Checked 30 mins later im 10mmols! Checked an hour later, 10.2!
Usually i just fall away with bsugars, but im not sure if it was the heat or not. I was running very hard because of the heat, but i had a correction bolus of just 1 unit of novorapid.
Im a bit concerned that i should have just let the numbers come down 'naturally'. This is the first time i have had to bolus because of high numbers post exercises. Im wary of post exercise lows. Did i do the right thing here? I sometimes get minor post exercise little spikes, which i thought maybe the leftover carbs i sometimes use during exercise, but this one was really high. I often have a banana post workout because im usually on the low side.
Any info on this would be good! Thanks :)

A lot of the "energy chews" have maltodextrose in the. In my experience, not all that much, as I avoid them, those can keep pushing your BG up for a couple of hours after you take them. I usually just lug jelly beans and Gatorade along, as they work faster. If my BG is crashing, I want something that will work fast. Gu and chews, etc. have worked ok for me at the start of runs but not so much during. I have a big collection of Gu, etc. that people have passed out at races. I don't want to throw them out but I use the fast acting stuff.

i do take beans with me too, i take a small doggy bag of chews/beansetc. I have just purchased some gatorade 'prime' for that quick hit which i will plan to use 15 mins before hard workouts i think.
So matlodextrose is a bit slow in the delivery? I will have to remember that. Anyway its coming up on lunch here and i dont want to insulin stack so im in 2 minds on what to do with my cup of rice lunch tradition!

I try to eat whatever meal after I go running. As far as Gatorade, do they have the powdered stuff there? The 20 oz or whatever bottles are expen$ive so I get the powder, that makes like 5 gallons for $3.99 or so, less if it's on sale. That also has the advantage that you can "tailor" it and dump in as much as you need for whatever size run you are on, 12G of carbs, 30G of carbs, 50G of carbs, etc.