I encountered the same issue starting today—everything was fine yesterday. Then I realized that this problem was resolved in this commit: https://github.com/PMassicotte/gtrendsR/commit/849fbf780768e69faa3b1dbd373dd55b38acdcbd. To fix it, install the development version instead of the CRAN version, and the issue should be resolved.

devtools::install_github("PMassicotte/gtrendsR")