SQL exception when showing a calculated field

I have a column Temperature (string)that looks like this “temperature”: { “tC”: “double”,“tF”: “double”} in glue:
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I have created a calculated field for Temperature (C) where i use: “parseDecimal((substring (split({Temperature},‘,’,1),5,4)))”

I can see the new column fine in Edit Data but somehow got the SQL exception error in the analysis:
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Not sure where the calculated field goes wrong since I did convert it to Decimal after the substring and able to see it fine in the edit dataset page.

Is this a direct query dataset or does it use SPICE? What database does the data come from?
If I were you, I would start by testing shorter expressions to better understand what part of expression might be causing the problem, for example initially not call parseDecimal and look at the strings returned by the substring.
Additionally, I would try to check if the issue is caused by some rows (e.g. Temperature is null in some cases). If that is the case, visual might render if you add a filter to only look at few rows.