This problem was reported few months ago and as there is a workaround, may be not considered at this time.
As i'm quite tired to apply the workaround I submit it again to see how many people are affected.
Problem arise when a pseudo is defined with an ampersand. Generally two names. Exemple 'Christelle & Fiona', or 'Doriane & Romain'.
Problem is : it is impossible to enter the '&' sign in a normal way in the middle of the name, no character appears when the key is typed.
This behaviour was visible on Win10, Chrome (a lot of versions since months, years) in any language selected and also with virtual keyboard.
Workaround is to type the whole pseudo without the '&' sign 'ChristelleFiona' and after that come back with arrow to insert the ' & '. : tedious
May be a small thing to change at input routine, or could help with this workaround if not solved