I've also noticed that the prices on the second leg fluctuate based on the first leg, which is really frustrating.

For example, I'm pricing flights on Mar 11 flying into either JRO or NBO and out of NBO. If I pick the least expensive flight to JRO ($406), the least expensive return is $799. But if I pick a ~$500ish flight, the same exact return drops to $710. If I pick a $355 flight into NBO, then that same return is priced at $761. If I take the $589 flight into NBO, now the return is $727.

The same thing happened when I was buying an SFO-CHI round trip a couple weeks ago. It really seems to negate any advantage of the "one way" pricing.