This is an unusual configuration. Do most beekeepers in your area run double deeps over winter, or did you just want some traditional frames of honey for yourself? In the colder parts of Australia, I have heard of people using a deep and a WSP or an ideal, but running double deeps without allowing the queen access to the second deep is not common from what I have heard. Just curious.
I probably would have waited a little longer. I keep banging this same old drum, but I have 3 rules for adding a box, whether it is a second brood box, a traditional honey super, or a Flow super (same rules for each):
All frames have mostly fully drawn comb, and
- The drawn comb is 80% full of brood, honey or pollen, and
- Every frame is completely covered with bees
If you make sure that all of those are true, then you will have enough bees to work, defend and heat the new box.
That is a start, but many of us have pushed some burr comb or painted melted wax onto the Flow frames to help the bees get the message that this is a useable part of the hive. Burr comb is the easiest - during an inspection, just scrape a little excess wax from another frame, and gently “butter” it onto the wavy plastic face of the Flow frame. When I did that, my bees were in the box within 2 days, and filling it within a couple of weeks.
Your bees have not started waxing the plastic cells yet (your photograph and video both show that), so I would suggest using some wax to help them accept the frames. Be aware that they will not use the Flow super until they have enough bees and a good nectar flow. If you are currently in a dearth, they won’t use it at all, even if you wax it.
I agree, they are fighting. The most likely reason would be robbers. Do you have an upper entrance? Any signs of fighting around the hive entrance(s)? If there are a lot of dead bees, you might want to install a robbing screen. If as @Kirsten_Redlich says, you are not in a good flow at the moment, it might even help to take the Flow super off, so that your bees have less space to defend from robbers etc. You can always put it back later in the season, if they have fulfilled the 3 golden rules above.
Please let us know what you decide and how it goes when you have time.