Simulation's generated chart only displays sell arrows, not buy arrows, despite buys happening during simulation

[Orwi53]

System information

• OS Platform and Distribution: Ubuntu Mate 18.04
• Zenbot branch: [unstable] Exchanges: update-products 5539
• NodeJS version: v12.16.1
• Exact command to reproduce (include everything): ./zenbot.sh sim --days 30
• Did I make any changes to conf-sample.js?: Only change: c.selector = 'poloniex.ETH-BTC'
• Additional information: Using nvm to manage node version

Describe the problem

Simulation's generated chart only displays sell arrows, not buy arrows. See screenshot.

Source code / Error logs

How to reproduce:

sudo apt-get install build-essential mongodb -y
git clone https://github.com/deviavir/zenbot.git
cd zenbot
npm install
Changed selector to: c.selector = 'poloniex.ETH-BTC'
./zenbot.sh backfill poloniex.ETH-BTC --days 14 
./zenbot.sh sim --days 14 --period 30m
Open generated html file with chart