Combination of multi-argument function and List.map <lambda> gives "bad contract type" compilation error

Using List.map withing a function with multiple arguments gives "ligo: generated Michelson contract failed to typecheck: bad contract type" compilation error (ligo compile-contract example2.mligo main). example2.mligo

However, if balance_of function signature changed to a single tuple argument, the contract compiles w/o errors. example2_fixed.mligo

Ligo version:

Rolling release
Hash: 2c03ebf2
Date: 2020-02-12 16:12:21 +0000
CI job id: 434997427