type [<Measure>] m
let a = {|a=1<m>|}
//      ^^^^^^^^^^

the tooling has issue here because there is no space before |}.

FS0010: Unexpected symbol '}' in expression

the workaround:

let a = {|a=1<m> |}

I report the issue because it is a bit inconsistent, it works when no unit of measure is involved, and it works for a nominal record type.

maybe the compiler can accept the code or, tells me that the closing of the anonymous record expression needs to be one space appart in this case.