Broken unicode characters appearing and breaking layout when using fancy_grid format

[Fortnox]

In certain circumstances Tabulate inserts several broken Unicode characters when using the fancy_grid format. This breaks the layout. It happens with some tables and not with others; I've been unable to figure out what is causing it.

Here is a test case. With the following headers:

Time
Monday
Tuesday
Wednesday
Thursday
Friday

And the following data:

['08:15', '', '', '', '', '']
['09:15', '', '', '', '', '(dancing|carol|hall)']
['10:15', '', '', '', '', '(glass_blowing|carol|hall)']
['11:15', '', '', '', '', '(glass_blowing|carol|hall)']
['12:15', '', '', '', '', '']
['13:15', '(glass_blowing|dave|hall)', '(glass_blowing|dave|hall)', '', '', '(glass_blowing|carol|hall)']
['14:15', '(glass_blowing|dave|hall)', '(glass_blowing|dave|hall)', '', '', '(glass_blowing|carol|hall)']
['15:15', '(glass_blowing|dave|hall)', '(glass_blowing|dave|hall)', '', '', '(glass_blowing|carol|hall)']
['16:15', '', '', '', '', '']
['17:15', '', '', '', '', '']
['18:15', '', '', '', '', '']

The following table with several broken unicode characters is produced:

╒════════╤═══════════════════════════╤═══════════════════════════╤═════════════╤════════════╤════════════════════════════╕
│ Time   │ Monday                    │ Tuesday                   │ Wednesday   │ Thursday   │ Friday                     │
╞════════╪═══════════════════════════╪═══════════════════════════╪═════════════╪════════════╪════════════════════════════╡
│ 08:15  │                           │                           │             │            │                            │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 09:15  │                           │                           │             │            │ (dancing|carol|hall)       │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 10:15  │                           │                           │             │            │ (glass_blowing|carol|hall) │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 11:15  │                           │                           │             │            │ (glass_blowing|carol|hall) │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 12:15  │                           │                           │             │            │                            │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 13:15  │ (glass_blowing|dave|hall) │ (glass_blowing|dave|hall) │             │            │ (glass_blowing|carol|hall) │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 14:15  │ (glass_blowing|dave|hall) │ (glass_blowing|dave|hall) │             │            │ (glass_blowing|carol|hall) │
├────────┼───────────���───────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 15:15  │ (glass_blowing|dave|hall) │ (glass_blowing|dave|hall) │             │            │ (glass_blowing|carol|hall) │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 16:15  │                           │                           │             │            │                            │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 17:15  │                           │                           │             │            │                            │
├────────┼───────────────────────────┼───────────────────────────┼─────────────┼────────────┼────────────────────────────┤
│ 18:15  │                           │                           │             │            │                            │
╘════════╧═══════════════════════════╧═══════════════════════════╧═════════════╧════════════╧════════════════════════════╛

Reproduced on Ubuntu Bash. I also tried this with Windows CMD and was told the response could not be encoded due to character '\u2552' which is 'bengali currency numerator one less than the denominator', "৸" (http://unicodelookup.com/#2552/1).