I understand from CIC website that this travel document is only for a single entry to Canada.
Travel document counterfoils are normally issued for a single entry to Canada. If you meet the residency obligation but are residing outside of Canada on a long-term basis (for example, if you are a permanent resident accompanying a Canadian citizen spouse), you may want to request a long-term multiple entry travel document. To do so, you should include a cover letter explaining your circumstances and requesting a multiple entry travel document. These can be issued for up to five years but cannot extend beyond the expiry date of your passport