CL-300 fractional jet crew reported a pneumatic pylon bleed malfunction during climb. The crew returned to the departure airport and landed.

Narrative

Climbing through ~17;000 ft; a red Crew Alert System (CAS) message of 'L Pylon Bleed Leak' was displayed. The single memory item of 'thrust lever on affected engine to IDLE' was accomplished and the message cleared. The QRH was opened and the short checklist was completed. We continued climbing to our assigned altitude of FL200 for our short flight to ZZZ1. Very briefly; we discussed whether to continue on for 27 minutes to our destination; whether to keep the affected engine running; diverting to ZZZ2 for a longer runway; or if there were any other indications or obvious causes that would prove or disprove the message. About a minute later; I decided the safest course of action was to return to our departure airport; which was only 5-10 minutes away. As we were at a comparably low altitude; VMC; and the message had cleared; I did not [request priority handling]. ATC was notified and we returned to ZZZ uneventfully. As a pre-caution; even with the affected engine at IDLE; we ran the Single-Engine Approach and Landing checklist. Cause: After landing; mechanics inspected a bleed line via the Aft Equipment Bay. A particular area of one line was suspected of possibly having a pin-hole sized leak.After landing; shutdown; and passenger accommodation; we discussed the event; possible options; and whether we had proceeded in an appropriate manner. Both of us expressed ideas that we had little or no other options than what we did do and that we had completed all relevant checklists and explored all other logical options.Suggestion: Follow all relevant protocals; including memory items and checklists and utilize thorough and honest crew communications.