Not sure if this truly helps but it is something that i think it's still worth to give a shot and see if it changes anything.
1. First make sure you have the latest firmware installed for both your phone and the freebud 2 pro.
2. If you already have your freebud 2 pro paired on your device, try to unpair it first.
3. Factory reset your Freebuds 2 Pro by placing both earbuds into the battery case, press and hold the pairing button on the case and do not let go. Wait for it to first flash blue > red while still holding the button, look at the front 4 LED battery indicators. Once the 4 lights start blinking release the button and wait for a few sec. The 4 lights should then go away and the LED in the case should now start blinking with blue light as if it is in pairing mode. Wait for the light to go away then close the case.
4. Now on your phone, first disable your Bluetooth, then go to Settings > Apps > Apps and tap on the 3 dots on the top right. then select Show system processes.
5. In the search field type in Bluetooth, you should see 3 items ( Bluetooth, Bluetooth MIDI Service and Import via Bluetooth)
6. Select on Bluetooth then tap on Force Stop then tap on Storage and Tap on both Clear Cache and Clear Data to proceed on deleting the app data. Generally this should be enough but if you wish to play safe, do the same for the other 2 items which are Bluetooth MIDI Services and Import via Bluetooth.
7. Next in the search field type device connection and you should see Device Connection service. Do the same for this, Force Stop then tap on Storage and proceed to delete the app data.
8. Restart your device.
After you have done all the above, now go to Settings > Device connectivity > Bluetooth. Turn on your Bluetooth and proceed to open your Freebud 2 Pro battery case and see if you get any pop up, if you don't get any then just do the usual pairing by pressing and holding the pair button on your Freebuds 2 Pro case for about 2secs for the blue LED to blink then proceed to search the earbuds with your phone and pair it. After doing so see if you get the pop up as shown in my original post. If you do not get the pop up, try tap on the gear icon of your Freebuds 2 Pro while connected to your device and see if you are able to see those additional settings for the earbuds as shown in my screenshot. If you do not see them then it is pretty unlikely you will get the pop up. If you do try enable the Auto download over Wifi settings and also perform a check firmware version from there as well (not from the app and do try to do this while connected to wifi). Once done. just keep the the earbuds connected for a bit. maybe about 15-20mins later try put back your earbuds to the case and wait for a bit then open the case again and see if you get the pop up now.
Disclaimer: the above is not an official method / fix to the issue. but rather some information I have gathered from other user's experience. while this has been tested to not damage anything, still I do not take any responsibility should anything goes on with your devices after performing the above steps. So do it at your own risk.
PS : on a side note, if anyone encounter issue like failing when attempt to update your Freebuds 2 Pro via the app, you may try use Step.7 then repeat the upgrade process. This is one of the known "fix" that I find from other users as well.