Hello Janez Jalen,
Sorry you are experiencing this issue, as you should be able to have 10 site to site and 10 client to gateway configurations I am wondering as they are both using IPsec parameters that the RV130 is getting confused.
On that note I recommend first to upgrade to the latest firmware (if you have not done so). Link to the latest firmware: https://software.cisco.com/download/release.html?mdfid=285026142&softwareid=282465789&release=1.0.1.3&relind=AVAILABLE&rellifecycle=&reltype=latest
Check the encryption that you are using for the client to gateway and change it so it is not the same as your site to site VPN's encryption. This is to help differentiate the tunnels to potentially not to cause any confusion in the router.
Other than that getting the IPsec logs to see how the tunnels are negotiating will be the next step to see how the router is handling the requests.
Hope this helps,
Michael D.
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