`./sandbox up` fails upon first time run

I'm following the TICK stack [getting setup documentation][1]. Executing `./sandbox up` fails with the following message:
```
=> CANCELED ...
failed to parse stage name "kapacitor:kapacitor:latest": invalid reference format
```
The thing to pay attention to here is **kapacitor:kapacitor:latest**. That is likely because of the [.env][2] which adds the image name to the tag variables.

Replacing the contents of the [.env][2] from
```
TELEGRAF_TAG=telegraf:latest
INFLUXDB_TAG=influxdb:1.8
CHRONOGRAF_TAG=chronograf:latest
KAPACITOR_TAG=kapacitor:latest
```
to
```
TELEGRAF_TAG=latest
INFLUXDB_TAG=1.8
CHRONOGRAF_TAG=latest
KAPACITOR_TAG=latest
```
fixed the issue

[1]: https://docs.influxdata.com/platform/install-and-deploy/deploying/sandbox-install/#download-and-run-the-sandbox
[2]: https://github.com/influxdata/sandbox/blob/master/.env