This may be a question for Textra developers instead, but I love SwiftKey so I thought I'd see what you guys thought first.
When I click the "Plus" sign to add media to a SMS message, I usually hit either the emoji category or the photo category.
Regardless of which one I pick, SwiftKey stays "open" and does not disappear -- I can sort of pick a picture from the edge underneath the keyboard, but it never disappears. I have tried clearing cache, rebooting, etc.
I am using a Samsung Galaxy Note 8 from Verizon.
EDIT -- I found that if I leave a text message open, turn the display off my phone, then turn it back on, about 30-50% of the time it will actually close the keyboard and let me pick an image or emoji as it normally does. If you think this is a Textra issue I will post there. I have paid for both apps.
I also use the SwiftKey Beta app instead of the regular.