I noticed 2 format issues:
Import : File created by Topodroid X as *th (Therion) are not readable by CRP getting the following message: No (...) Therion (...) format in xxxxxx.th
Export : File created by CRP as *.kml are readable by Google Earth but not by QGIS. Comparison between the actual file format of the issued by CRP and the kml file issued by Google Earth (i.e. file created by CRP opened in G-Earth and saved again) show significant differences, which are likely to explain the issue.

1) I have tried importing Therion files straight out from TopoDroid as the Notes written in TD are not exported in *.csv file.
I suppose if several softwares use the csv format as import format, it might be more complicated for me to ask Marco Corvi to make such a change.

2) Done

Got a couple of email exchange with Marco,

Re: Therion import : looks like the only difference between *.th from TD and from Therion is the very first line i.e.: "encoding utf-8".
As adding this line to a *.th file issued by TD, seems to make CRP happy on import, he's going to add that first line to the *.th export

Re csv import : at the moment, the only way to get the Notes (=splay/shot comments) from TD in the csv format is to export the raw data as well (tick box on export). But CRP doesn't seems to like the extra raw data. I have suggested to add the notes within the default export. will see what he says.

At the moment, the only way I have found to get the Notes imported in CRP is to use *.tro format.

great thanks!

Got an email from Marco, shot/splay notes will be added to topodroid regular csv export with next release.