Problems with typing fast seems to be inherent to the keyboard. It actually happens when multiple keys are pressed, maybe because you're typing so fast that the keys don't have time to fully raise.
On the UK/Psion 5 keyboard layout, I discovered these key presses generate extra keys when typed extremely rapidly or pressed at the same time:
Right Shift+TE -> TE[Shift+Up]
Right Shift+LT -> LRT
Right Shift+RL -> RLT
Left Shift+() -> ( C ) (Ignore the spaces between characters. It generates a left parenthesis, a capital C, then a right parenthesis with no spaces in between. The forum turns it into a copyright symbol if I try to type that without spaces)
tdf -> tdwf
Right Shift+SF -> S~F
I've tested on both a Gemini and a Cosmo (same layout), and they both do the same thing for all of these, so it doesn't seem to be a one-off device problem, but an issue inherit to the keyboard's driver, firmware, design, or something. I tried different keyboard and autocorrect settings, but they don't seem to have any effect.
I do coding on my device, so typing some of these are really common for me, like typing "()" for a function call with no parameters, and a C library I use prefixes all functions with TE. It's really annoying.
There's also a problem with tab activating caps lock, even when Fn isn't being held. If you just tap and release Fn, and the next key press is tab, caps lock will turn on even though Fn isn't being held. It can also happen as part of a key combination. Pressing Fn+Left Arrow to generate a home key press, then pressing tab to try to indent will instead turn on caps lock without registering a tab. This is another common key sequence when programming.
There seems to be a slight difference in the way caps lock registers when doing this. In Termux, if I press Fn+Tab to turn on caps lock, caps lock turns on and Termux brings up a menu, but if I press Fn, release it, then press tab, caps lock turns on without Termux opening the menu.
One issue I noticed the Gemini had that was fixed in the Cosmo is Alt+Tab turning on caps lock.
I don't know if this happens in Linux, I've only tried Android.
I wrote about these to the
Cosmo tech support page about two weeks ago, so Planet Computers should know about this, but haven't I received a reply from them. Maybe this should be posted to the Astro Slide Indiegogo to encourage them to fix these problems?