I will ask him in more detail next time I see him. I will mention this study or ask if he’s seen it.

It's worth a read, wouldn't want my son playing on one frankly.

Here's their short summary of the data:

AGPs in professional rugby:

There was no significant difference in the incidence, severity or burden of match injuries between artificial turf and grass for the 2017-18 season.
When the data collected over the past five seasons is combined, the incidence of match injuries on natural grass and artificial turf are not different. However, the severity of match injuries on artificial turf is greater than that on natural grass, with an injury sustained on artificial turf lasting, on average, nine days more than one sustained on natural grass (natural grass, 30 days; artificial turf, 39 days). Consequently, the burden of injuries on artificial turf pitches is higher than those on natural grass.
When considering injury risk by body location, both severity and burden were greater for lower limb match injuries sustained on artificial turf with this being most marked for hamstring and foot and toe injuries.
When combining three seasons of training injury data to compare injuries on artificial turf versus natural grass, a similar trend to match injuries is apparent with similar incidence on both turf types while severity and burden and significantly higher on artificial turf.

Here's what the RFU is doing as a result:

4. Artificial grass pitches (AGP): Collaborate with World Rugby on their ongoing review of the appropriate performance standard and post-installation testing and maintenance requirements for AGPs in professional rugby union.  In addition, we will undertake new research to better understand the grip release characteristics of different types and styles of rugby boots. We believe that understanding the unique interaction between a player’s boot and an AGP will enable us to provide evidence-based guidance to players regarding the most appropriate boots to wear on AGPs and mitigate injury risk.