R github package w/ devtools: warning unknown macro '\item'

I made a package with the help of RStudio & devtools for namespace, DESCRIPTION & Roxygen2 for the man pages. This worked fine, and the help pages I've recently added worked too. I decided to add author name, email, and some details. Initially by manually editing the man page file (BAD) then editing the R script Roxygen2 parts & pushing the change to the Rm file with document()

But: when I install my package

devtools::install_github('SimonDedman/gbm.auto')

I get the following warnings:

Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:35: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:37: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:39: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:41: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:43: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:45: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:47: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:49: unknown macro '\item'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:51: unexpected section header '\value'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:55: unexpected section header '\description'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:65: unexpected section header '\examples'
Warning: /tmp/RtmpNladba/devtools27303e05b1fc/SimonDedman-gbm.auto-dbe3cb0/man/gbm.valuemap.Rd:69: unexpected END_OF_INPUT ''

Those items are just simple @param arguments which i've not changed, look fine and worked before. Ditto the value / description / examples arguments, which are all standard (but probably a downstream issue which will get solved once the upstream issue is fixed).

Can anyone think what might cause this? None of my help pages are clickable now, even though one would have thought that whatever this problem is with the one script (gbm.valuemap.R), the others should be fine?

Thanks in advance.