I can confirm this bug on 0.92 on KDE Neon/Ubuntu 16.04. Have the same distro installed on a workstation desktop and on a cheaper laptop and in both cases, I get the same error message as the original bug description when trying to save as an .odg file.
I've tried both "Save as" and "Save a copy" and have tried, in both, typing the extension while selecting "Guess from extension" and choosing the actual extension from the drop down list.
I can confirm this bug on 0.92 on KDE Neon/Ubuntu 16.04. Have the same distro installed on a workstation desktop and on a cheaper laptop and in both cases, I get the same error message as the original bug description when trying to save as an .odg file.
I've tried both "Save as" and "Save a copy" and have tried, in both, typing the extension while selecting "Guess from extension" and choosing the actual extension from the drop down list.