tsocks with svn - failure

tsocks is a program that will "sockify" any application. It does so by watching the application and rewriting any networking requests to go through the socks server you specify in tsocks.conf.

You can either use tsocks by running tsocks command [arguments] or by running tsocks on followed by the commands you want to run. You turn it off by running tsocks off.

I ran into an annoying error when using tsocks to sockify subversion. I got the error

svn: OPTIONS of '...': could not connect to server (...)

It turns out that using "tsocks svn up" failed this way, but if I tried the second possibility (tsocks on; svn up; tsocks off) it works.
I have no clue why this might be.