Red arrows indicating conditional or initiation links appear standard in the TPD. This arrows can not be deleted, when deleting and saving, they appear again. In addition, when a 'transaction status' is relocated, the red arrows keep their initial 'starting point'. Causing red arrows across the whole diagram. Browsers: Chrome and FireFox. Example: TPD of 'Parking'.
These red arrows are a feature, not a bug. They do originate from the PSD "Enforcement Simulation PSD part 1". You will find them documented in "DEMO-3 Way of Working version 3" slide 19.