Don't use webgl but "webgl setup failed possibly due to..."

I do not (consciously) use any webgl routines. But when I plot a 3D surface I get the following message: “webgl setup failed possibly due to false preserveDrawingBuffer config. The mobile/tablet device may not be detected by is-mobile module. Enabling preserveDrawingBuffer in second attempt to create webgl scene…”.

The error message is annoying but does not prevent the correct, interactive display of the surface plot.

I checked the source code in plotly.js (v2.0.0-rc.0) and saw that in:

var mobileRE = /(android|bb\d+|meego).+mobile|avantgo|bada/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)/|plucker|pocket|psp|series[46]0|symbian|treo|up.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i

var tabletRE = /(android|bb\d+|meego).+mobile|avantgo|bada/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)/|plucker|pocket|psp|series[46]0|symbian|treo|up.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino|android|ipad|playbook|silk/i

the iPad is not included. So I changed ip(hone|od) to ip(ad|hone|od). This did not help.

I have had this messaging problem with older versions of plotly.js; it did not begin with v2.0.0-rc.0.

Does anyone have an explanation or, better yet, a fix?

Thank you for any help you can bring to this.