UPDATE: The #REF! errors were not returned randomly in a broad sense, they appear sometimes and once the first occurrence appear on one cell then it repeats to the cells below it.

This looks to be a latency problem inherent to GOOGLEFINANCE(), as was previously mentioned by Normal in a comment to the question.

In order to have a "rock-solid formula" instead of using GOOGLEFINANCE directly in column E use an auxiliary sheet to hold the historical currency conversion rates as fixed values instead of calculated values through a formula.

You could use GOOGLEFINANCE() to get that data but then copy and paste values only.

Short answer before the OP shared a demo spreadsheet

Instead of using ambiguous date format (00/00/0000) use a explicit one like

• dd/mmm/yyyy
• mmm/dd/yyyy

among others

Explanation

The problem could be due to the regional settings / date format of your spreadsheet / data.

I just tried to reproduce the problem but it works fine in my environment:

• Date format: dd/mm/yyyy
• Regional settings: Mexico
• Account language: Spanish Latin America
• Always show the function names in English

Reference

• GOOGLEFINANCE - Google Docs editors Help

Partial short answer

The formula in I4 has some syntax errors

• Use of the wrong quotation character
• Use of equal sign after commas

Also, the formulas in I3 and I4 have some programming errors:

• Wrong references
• "Unnecessary complexity"

Explanation

Syntax errors

Quotation marks

Modern applications use a large number of characters some of them are visually very similar like "(U+0022 QUOTATION MARK), ” (U+201D RIGHT DOUBLE QUOTATION MARK) and ʺ(U+02BA MODIFIER LETTER DOUBLE PRIME) but for technical purposes, like enclosing strings in spreadsheet formulas, " (U+0022 QUOTATION MARK) should be used. It's worth to say that some text processors like Microsoft Word could automatically replace " by ” so when using and external application as a helper to write complex formulas the related feature should be turned off.

Equal sign

The equal sign could be used as an operator in spreadsheet formulas at the beginning of a formula or as a comparison operator, but not after the function arguments separator (comma or semicolon, according to the spreadsheet locale settings)

Programming errors

Yes, writing a spreadsheet formula makes people to be programmers but usually they are called analysts or just spreadsheet users.

Wrong references

The formula in I4 include references to columns that don't exists (M4,K4,S4,L4)

Unnecessary complexity

The formulas in I3 and I4 use COUNTIF to do a comparisons and the add operator to check if all the required conditions are met. The same could be done in a simpler way by using comparison operators and the boolean functions. While complex ways to do things could work, when something fails, one thing to try is to reduce the complexity.

The following formula is equivalent to the I3 formula but "simpler" (from a "programming" point of view):

=IF(AND(D3<"9:31",E3>65,F3>65,G3>11,H3<"10:01"),"P","F")