Internet connection bug on trisquel_9.0_amd64.iso (version of June 7, 2020)

This post to notify you of an internet connection problem; when I indeed surf on the canvas after a certain time no more connection is possible, whatever the site visited: I am therefore obliged to disconnect / reconnect so that it works again (I thought that the problem originated from Technoethical N150 Mini Wi-Fi USB Adapter but by testing the dongle with PureOs I cannot reproduce the problem).