Error unique to Safari web browser that I have a work around for and am posting in case others encounter the issue
The error is:
When setting the wrap width of TextStim: [Name of stim]
No default wrap width for unit: undefined
I had used the from exp settings option as my units (in the builder), with these set to height, the issue seems to be that Safari could not access the experiment settings units, and so I had to go through and make sure all stimuli units were set as height manually.
I am using Psychopy3, installed 28th April 2020
Note: This may not be unique to text stimuli - however this is where the error manifested - I changed units for all stimuli.