Most probably, Travis webhook changed in these 10 months in a backward-incompatible way (I do remember topics that suggest so: GitHub services to Webhooks migration update, No new builds being triggered, Double builds for all merges and PRs).
So you need to:
- Disable CI for the project in https://travis-ci.org/account/repositories
- Look through Webhooks and Integrations & services in Github project’s settings and delete anything Travis-related
- Re-enable CI for the project