Modem Manager GUI Crashes [error reporting]

Hello everyone,
I am having some issues with the Modem Manager GUI on my Trisquel machine (utilizing ThinkPenguin's USB modem).
The application appears to run fine, until you connect to a mobile network (especially utilizing the network manager).

Does anyone here have a similar issue? I was struggling to find the correct bug tracking system for the package.

```
usr@computer:~$ modem-manager-gui

(modem-manager-gui:2440): Gtk-WARNING **: 18:38:55.307: Theme parsing error: gtk.css:2250:35: The :focused pseudo-class is deprecated. Use :focus instead.
Connection manager: Network Manager >= 0.9.0
Modem manager: Modem Manager >= 0.7.0

** (modem-manager-gui:2440): WARNING **: 18:38:56.493: Network Manager >= 0.9.0: No such file or directory
Segmentation fault at address: 0x30
Stack trace:
1. /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_bit_lock+0x50) [0x7fdd676e0540]
2. /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_bit_lock+0x50) [0x7fdd676e0540]
3. /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_variant_n_children+0x1d) [0x7fdd6775a2dd]
4. /usr/lib/x86_64-linux-gnu/modem-manager-gui/modules/libmodcm_nm09.so(+0x3bc0) [0x7fdd5e24bbc0]
5. modem-manager-gui(mmguicore_connections_enum+0x6d) [0x5579da598d4d]
6. modem-manager-gui(+0x4a520) [0x5579da5b9520]
7. modem-manager-gui(mmguicore_devices_open+0x1c0) [0x5579da59df90]
8. modem-manager-gui(+0x415d2) [0x5579da5b05d2]
9. modem-manager-gui(+0x4a7a2) [0x5579da5b97a2]
usr@computer:~$
```

Funnily enough, if you delete the connection and then launch the application it appears to work fine. You can then add the new connection from the network manager and utilize the program. The issue only seems to arise when you connect to it as a saved connection—in which case it refuses to operate whatsoever.

If there are any additional details I can help provide to solve this issue—please do let me know!
And as always, I immensely appreciate all of your time and support.