Cannot pay 3c for Lionsmane subroutine alt cost

[filipesilva]

Link to bug replay: https://jinteki.net/bug-report/669a8b1e-6939-420d-a412-f2d1604555e2?b=0

Description:

Corp fired second lionsmane subroutine, but Runner could not pay credits for it.

[filipesilva]

Tried reproducing, but could not. Got the option as runner. Not really sure what the runner saw here, I was playing corp...