For the record, and so that we are all on the same page, here is my initial email to support. It clearly mentions the incorrect indicator calculations:

Hello

I'm a Zorro S user (invoice number XXXXXXX) and I'm hoping to get some help.

Is it possible for the MT4 platforms of individual brokers to be incompatible with the Zorro MT4 bridge?

I am asking because I have found that when connected to a certain broker in live trading mode, Zorro detects obviously erroneous ticks. I can find no trace of these erroneous ticks in the MT4 chart, nor in the MT4 history centre. No trades have so far been executed at or close to these levels, which makes me question whether these ticks actually existed. Is it possible that the Zorro bridge could somehow register a tick that never existed?

Although no trades have been executed at these erroneous tick levels, my system uses the recent high and recent low by way of the HH() and LL() functions. These erroneous ticks have a significant impact on the values calculated by these functions (verified by printing indicator values to the log file) and several trades have been executed as a result, when they clearly shouldn't have.

This issue first came to my attention last night on EUR/USD. Attached is the image that Zorro created - although the quality is not great (I am running my VPS using 15-bit color to free up as much RAM as possible) you can see the erroneous ticks occurring between 7 and 8 PM at values of approximately 2.3 and 1.7. These ticks dwarf the scale and therefore the rest of the price curve is barely visible. Clearly EUR/USD never traded at these levels and there is no sign of these ticks in the broker's MT4 feed.