version 60.0.3112.114 (officail build) unknown (64 bit)
Platform  9592。91。0 （official build) dev-channel clapper test 
Firmware Google_Clapper.5216.199.7


Steps:
1. Switch to US keyboard compact layout
2. Tap any letter, e.g.  <a>
3. Not submitted , switch to Full layout
4. Tap <a> again 

Actual:
 The first candidate word display aa , will remember last letter tapped in compact layout

Note:
If from Full layout switch to Compact layout, this issue not repro