Seems "future leakage" exit, need confirm

**Describe the bug**

In demo NeurIPS2018, close/low/high value are used as states, it seems future leakage exist?

**To Reproduce**
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2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior**
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**Screenshots**
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**Desktop (please complete the following information):**
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- Version [e.g. 22]

**Smartphone (please complete the following information):**
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- OS: [e.g. iOS8.1]
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**Additional context**
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