fix an issue where using hires fix with refiner on first pass with medvram...

fix an issue where using hires fix with refiner on first pass with medvram would cause an exception when generating

modules/processing.py

@@ -1315,7 +1315,7 @@ class StableDiffusionProcessingTxt2Img(StableDiffusionProcessing):
             if shared.opts.hires_fix_use_firstpass_conds:
                 self.calculate_hr_conds()
 
-            elif lowvram.is_enabled(shared.sd_model):  # if in lowvram mode, we need to calculate conds right away, before the cond NN is unloaded
+            elif lowvram.is_enabled(shared.sd_model) and shared.sd_model.sd_checkpoint_info == sd_models.select_checkpoint():  # if in lowvram mode, we need to calculate conds right away, before the cond NN is unloaded
                 with devices.autocast():
                     extra_networks.activate(self, self.hr_extra_network_data)