SSMS "Intellisense" behaviour is driving me demented

That started very recently. (v18)
Use one letter aliases like this:

SELECT * 
FROM tbl_References as r
WHERE r

However, when I type a dot after the alias,  Intellisense replaces alias by a function name like this:
c -> CAST
r -> RADIANS
s -> string_split
e -> ENCRYPTBYASYMKEY

SELECT * 
FROM tbl_References as r 
WHERE RADIANS.

Suggestions like "use longer aliases" - won't work. It is easier to turn off Intellisense completely.

Working with SSMS since SQL2000. Never seen such a behavior. 
Assume this is a new bug, possibly not from SSMS, but from a .NET framework