Strategy ATR TP/SL target doesn't stay 'locked' to my entry readings - pine-script-v5

Question

I want a strategy to Take Profit/Stop Loss to be based on the ATR (plus multiplier). However, I want it to be whatever the readings were at the point of entry, not simply the last candle (which is what it seems to be doing). Weird thing is that I have other strategies that use this approach, and they seem fine, so I'm really stumped by what I'm doing wrong.
Any help would be much appreciated!
// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © dave-browning
//#version=5
strategy("Dead-Cat Bounce", overlay = true, initial_capital = 1000, default_qty_value = 100, default_qty_type = strategy.percent_of_equity, currency = currency.GBP, commission_value = 0.05, use_bar_magnifier = true)
trendEMAlength = input.int(130, "Trend EMA Length")
fastSMALength = input.int(14, "Fast SMA Length")
tpATRmultiplyer = input.float(6.2, "Short TP ATR Multiplier")
slATRmultiplier = input.float(4, "Short SL ATR Multiplier")
//Trade Conditions
shortCondition = close > ta.sma(close, fastSMALength) and close < ta.ema(close, length=trendEMAlength)
notInTrade = strategy.position_size <= 0
atr = ta.atr(14)
ema=ta.ema(close, trendEMAlength)
plot(ta.sma(close,length=fastSMALength), color=color.blue, linewidth = 2)
plot(ta.ema(close, length=trendEMAlength), color=color.yellow, linewidth = 4)
plot(low - (atr * tpATRmultiplyer), color=color.green)
plot(high + (atr * slATRmultiplier), color=color.red)
if shortCondition and notInTrade
stopLoss = (high + (atr * slATRmultiplier))
takeProfit = (low - (atr * tpATRmultiplyer))
strategy.entry("Short", strategy.short)
strategy.exit("Short Exit", "Short", limit=takeProfit, stop=stopLoss)