Is it lawful to collect tax from recipient of supply on reverse charge basis

Yes, as long as the tax is on the subject of levy, Government is free to collect this tax from any person – either the supplier or the recipient or anyone else. Even a third party can be called upon to deposit the tax provided there is some nexus such as collection of payment for the supply between two other persons.

(ICAI FAQ PUBLICATION 06-09-2017 REVERSE CHARGE: FAQ NO. 21)