Symbol-list-not-being-read-on-strategy-update

I've just updated the list of pairs being traded by a strategy. I've created a new file with the new symbols formatted the same as the previous version (which was running fine). I've also created corresponding new dataset to match and updated it.

I've also updated the strategy settings to point to the new dataset and also edited the script to point to the correct new pairs file.

However, when I run the script I get the following errors (these are for all symbols that weren't in the previous file). The new pairs file is at the end of this post, which shows that the errored symbols are actually present in the pairs file.

CODE:
Initialize Exception (FBP) Line 64 - Symbol not found in Pairs file: FBP
Initialize Exception (AGCO) Line 64 - Symbol not found in Pairs file: AGCO
Initialize Exception (FIBK) Line 64 - Symbol not found in Pairs file: FIBK
Initialize Exception (FTS) Line 64 - Symbol not found in Pairs file: FTS
Initialize Exception (FUL) Line 64 - Symbol not found in Pairs file: FUL
Initialize Exception (ETR) Line 64 - Symbol not found in Pairs file: ETR
Initialize Exception (CUBE) Line 64 - Symbol not found in Pairs file: CUBE
Initialize Exception (PB) Line 64 - Symbol not found in Pairs file: PB
Initialize Exception (EIX) Line 64 - Symbol not found in Pairs file: EIX
Initialize Exception (PPBI) Line 64 - Symbol not found in Pairs file: PPBI
   at WealthScript9.MyStrategy.Initialize(BarHistory bars) in :line 64
   at WealthLab.Backtest.UserStrategyExecutor.AssetListener(List`1 symbols)

The code that reads the pairs file is:

CODE:
   //create pairs dictionary on-demand
            if (_pairs == null)
            {
               _pairs = new Dictionary<string, (string, double)>();
               SetGlobal("PairsData", _pairs);

               //load pairs file contents
               string fileName = Path.Combine(WLHost.Instance.DataFolder, "pairs2024_Jul.csv");
               if (!File.Exists(fileName))
                  throw new FileNotFoundException("Pairs file not found: " + fileName);
               string[] lines = File.ReadAllLines(fileName);
               foreach (string line in lines)
               {
                  if (line.Trim() == "")
                     continue;
                  string[] tokens = line.Split(';');
                  string[] pairTokens = tokens[0].Split('/');
                  (string, double) pw;
                  pw.Item1 = pairTokens[1];
                  pw.Item2 = Double.Parse(tokens[1], CultureInfo.InvariantCulture);
                  _pairs[pairTokens[0]] = pw;
               }
            }

...and the piece of code that throws the error is:

CODE:
   if (!_pairs.ContainsKey(bars.Symbol))
            throw new InvalidOperationException("Symbol not found in Pairs file: " + bars.Symbol);

I've clearly missed a crucial step but am stumped as to what. Thx

CODE:
ABCB/CADE;0.077
AGCO/DE;0.154
AOS/ITW;0.154
ARCC/TSLX;0.077
ASB/HBAN;0.077
CDNS/MANH;0.062
CUBE/FR;0.062
DRH/HST;0.062
EIX/EVRG;0.077
ETR/FE;0.077
FBP/MTB;0.077
FFBC/ONB;0.077
FIBK/UCBI;0.077
FTS/LNT;0.077
FUL/RPM;0.077
LADR/RITM;0.062
PB/PNC;0.077
PMT/RC;0.062
PPBI/VLY;0.077
QGEN/TMO;0.154