Hi,
I can confirm that this happens on CentOS as well.

Using username "cody".
<email address hidden>'s password:
Send automatic password
Attaching: [screen____1933.byobu]

^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^A^A^A

This happens periodically. Sometimes, I ctrl-c when logging in and it will automatically end up back at bash instead of byobu. This gives me some insight. Normally, I just restart my host but this is getting annoying.

Using username "cody".
<email address hidden>'s password:
Send automatic password
^C'import site' failed; use -v for traceback
Attaching: [screen____1933.byobu]

^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C
Using username "cody".
<email address hidden>'s password:
Send automatic password
^Ccody@hosting:[~]$ ^C
cody@hosting:[~]$ ^C

cody@hosting:[~]$ w
 20:13:59 up 1 day,  8:48,  9 users,  load average: 0.94, 0.72, 0.64
cody@hosting:[~]$ ps aux | grep byobu
cody      1933  0.0  0.1 135684 18212 ?        Ss   Oct21   1:20 SCREEN -S byobu -c /usr/share/byobu/profiles/byoburc /usr/bin/byobu-shell
cody      4774  0.0  0.0 106196  1576 pts/0    S+   03:26   0:00 /bin/sh -e /usr/local/bin/byobu-select-session
cody      4800  0.0  0.0 118792  1176 pts/0    S+   03:26   0:00  1933.byobu
cody     20387  0.0  0.0 106196  1576 pts/5    S+   20:08   0:00 /bin/sh -e /usr/local/bin/byobu-select-session
cody     20413  0.0  0.0 118792  1184 pts/5    S+   20:08   0:00  1933.byobu
cody     21296  0.0  0.0 106196  1572 pts/7    S+   20:12   0:00 /bin/sh -e /usr/local/bin/byobu-select-session
cody     21322  0.0  0.0 118792  1180 pts/7    S+   20:12   0:00  1933.byobu
cody     21709  0.0  0.0 103244   876 pts/8    S+   20:12   0:00 grep byobu
cody     28261  0.0  0.0 106196  1576 pts/3    S+   18:35   0:00 /bin/sh -e /usr/local/bin/byobu-select-session
cody     28287  0.0  0.0 118792  1180 pts/3    S+   18:35   0:00  1933.byobu
cody     32599  0.0  0.0 106196  1576 pts/6    S+   19:31   0:00 /bin/sh -e /usr/local/bin/byobu-select-session
cody     32625  0.0  0.0 118792  1180 pts/6    S+   19:31   0:00  1933.byobu

If I try to go back into byobu now, it appears to lock up as normal. I can try killing all byobu sessions. 

cody@hosting:[~]$ byobu --version
byobu version 5.86
WARNING: ulimit -u is too low
Screen version 4.00.03 (FAU) 23-Oct-06

I thought maybe it was because of the ulimit being too low (default 1024), I changed it to 10240, then tried to reopen byobu.

cody@hosting:[~]$ ulimit -u 10240 ;byobu --version
byobu version 5.86
Screen version 4.00.03 (FAU) 23-Oct-06
cody@hosting:[~]$ byobu --version
byobu version 5.86
Screen version 4.00.03 (FAU) 23-Oct-06
cody@hosting:[~]$ byobu
Attaching: [screen____1933.byobu]

I hit ctrl-z and it allowed me to background byobu.

Decided to kill all byobu via root and then went back to my account. Works fine now.

Seems as though screen is locking up. 
I'm not super smart on understanding what I'm doing, but this is what I know I can try providing.