Bi-directional translator on SPI bus

I'm faced with a problem.
What I have:
A custom board has a 5V-powered ADC on SPI bus and a TXB0104 bi-directional translator to go from 5V to 3.3V. I only have access to the headers that have the translated 3.3V SPI bus.

The problem is: I'm trying to use this board on a 5V system. So I got a TXB0104 breakout board from adafruit to translate the voltage back to 5V. So there are two TXB0104 boards, one on the custom board to translate 5V to 3.3V (no easy access) and another that is on a second custom PCB that translates 3.3V back to 5V. Everything worked on the breadboard. But the PCB version (I didn't design it) that exactly mapped the breadboard prototype is not working. The MO and SCK signals are all noisy and distorted. Here is an example:


What is causing it: I suspect that the IC is not designed to drive long wires (a few inches long but all twisted, again, not my doing). The spec sheet says that the IC drives the gates weakly and can be overwritten by strong HIGH or LOW to make it bi-directional. I guess cross talk is strong enough to confuse the IC. Adafruit has a blurb about it. Read the sentence in bold.

So what I attempted to solve the problem is to replace the TXB0104 breakout board with a 74HC4050. Let it shift MO, SCK, and CS to 3.3V and directly patch 3V3 MI to Arduino. The result is much cleaner SCK and MO signals but still noisy MI.

I am wondering what to do to resolve this issue. I think I'll try to use an input channel on 74HC4050 to follow the 3.3V output from TXB0104 so it won't need to see the long wire. I'll see if it works.

OK so I used the 4050 to boost the output of the MI line and it's a lot cleaner. Will place the IC on a PCB to reduce cross talk.