Issues with MQL5 Compiling - Undeclared Identifier

At the end of a production run, I went to export and then test strategies on an MT5 terminal and this error came up (seeing mqlcompilingerror pic). The three strategies attached have this error but it's only visible when you're not in pseudo-code. Attached is a screenshot of one (mql error). 


I found hundreds, if not potential thousands of this error. At first, I thought it was because of running them through the sequential optimizer but this was happening during the build phase!

Generally, I noticed this with strats that were using Raising/Falling/Changing direction signals. This affected both stock and extension indicators/signals. 

At the end of a production run, I went to export and then test strategies on an MT5 terminal and this error came up (seeing mqlcompilingerror pic). The three strategies attached have this error but it's only visible when you're not in pseudo-code. Attached is a screenshot of one (mql error). 

SQX will generate strategies with missing MQL5 code causing compiling errors. Signal blocks with rising/falling/changing direction (both stock and extensions) are mostly affected. 

I found hundreds, if not potential thousands of strategies with this error. At first, I thought it was because of running them through the sequential optimizer (changing their parameters) but this was happening during the build phase!